A month has passed since Danny Fenton's exposure to his parents' Ghost Portal turned him into a human-ghost hybrid. When his goth friend Sam changes the lunch menu to ultra-recycle vegetarian, the vengeful ghost/meat monster of the previous Casper high school lunch lady reanimates to bring meat justice back to the high school. Danny must channel his newfound powers into fighting this ghost while keeping them a secret from everybody except his two best friends.

Guest star: Patricia Heaton as the Lunch Lady Ghost

Danny has a major crush on the school's most beautiful girl, Paulina. He asks her to go to the big dance with him by giving her an amulet he found. When his still-unpredictable ghost abilities cause problems at school, Mr. Lancer requests a parent-teacher conference with his dad. Using his newfound ability to "overshadow" or inhabit another's body, he talks his way out of trouble in his dad's body. More trouble awaits at the dance, however, when it turns out that the amulet he gave Paulina turns anybody into a huge ghost dragon when angered.

Up all night fighting the Box Ghost, Danny attracts the attention of a Ghost Hunter named Skulker, who vows to capture Danny Phantom, as he is rare and unique. The next day, Danny receives a D on his biology test, and Sam suggests that he earn extra credit by doing a report on the purple back gorilla. To help Danny manage his time, Tucker puts Danny's schedule into his PDA. In an attempt to capture Danny, Skulker sees Tucker's PDA and uses it to upgrade his armor. His power increases, but he becomes bound to Danny's schedule. Will Danny manage to evade capture by a ghostly villain and save his biology grade?

Guest star: Mathew St. Patrick as Skulker

Danny finds himself finally part of the "in crowd" at Casper High, but his newfound popularity strains his friendship with Sam and Tucker. Because the lab and household junk he sells to pay for his cool new outfit has been infused with a spectral influence, Technus, Master of All Things Electronic, is on the loose. It is up to Danny to save the city, make it to the party in time, and reconcile with Sam and Tucker.

After the Box Ghost destroys Danny's locker, he is assigned a new one: Locker 724. Everyone is afraid of that locker, but Danny does not know why. Meanwhile, Danny decides to get some "ghostly getback" on the bullies in school. It is later revealed that the former owner of his locker in the 1950s, Sidney Poindexter, was the main bully victim in his time. He punishes Danny for his actions by swapping bodies and dimensions with him, trapping Danny in a mirror world of his high school.

Guest star: Peter MacNicol as Sidney Poindexter

When a little girl's balloon string pulls an ancient mystical lamp to the ground, the lamp breaks and releases Desiree, a wishing ghost who grants every wish she hears but brings chaos with her magic. Thanks to a new ghost power, Danny stops her, but when Tucker's growing envy of Danny's powers drives him to wish for ghostly abilities, Desiree grants his wish. Initially annoyed by Tucker's new abilities, Danny must act quickly when he learns Tucker's envy will transform him into the strongest ghost boy ever. Will Danny reverse Desiree's wish-granting spell before its too late for his best friend?

Guest star: Peri Gilpin as Desiree

Jack brings his entire family to Wisconsin for his college reunion hosted by his old friend, Vlad Masters. While it's strange enough that Danny encounters ghosts on his vacation, what he learns about Vlad proves even more surprising: Vlad has hated Jack ever since Jack caused an accident in college— an accident that left him half-ghost, too. He has also tried to steal Maddie, the lost love of his life, away from Jack. After rendering Danny Phantom unconscious in a fight, Vlad sees Danny transform back into Danny Fenton and learns that his enemy's son shares a similar ghostly secret. With 20 years more experience with his ghost powers and motivated by a hatred for Jack, Vlad becomes Danny's archenemy.

Guest stars: Martin Mull as Vlad and Mathew St. Patrick as Skulker

Already afraid that his parents might get divorced, Danny accidentally knocks Jack's wedding anniversary gift to Maddie into the Ghost Zone. Determined to get it back, Danny ventures into the Ghost Zone for the first time. However, he is caught by a ghost warden, Walker, who makes up rules to retain order in his section of the Ghost Zone. Sentenced to 1,000 years in the Ghost Zone Prison, Danny is locked up alongside many of his ghostly enemies he has fought and sent back to the Ghost Zone. Luckily, he manages to persuade them to work with him to bust out of the prison. As the other ghosts escape, he returns to the prison cell to retrieve the gift and discovers that humans cannot be hurt by ghosts in the Ghost Zone, because in the Ghost Zone, humans are the ghosts.

Guest Star: Matthew St. Patrick as Skulker

Note: Starting with this episode, the Lunch Lady Ghost is now voiced by Kath Soucie for the remainder of the series.

A new guidance counsellor depresses most of the students in Casper High School. While outwardly peppy and spirited, she is a ghost feeding on the students' misery to remain perpetually young. Jazz attempts to investigate Danny's recent changes in personality. He attempts to elude her, but Jazz accidentally witnesses Danny transform into his ghost form. Jazz keeps his secret and waits until he is ready to tell her.

Danny has difficulty with a ghost dog, and every time it appears, it causes trouble. Within the Axion building, the ghost dog goes out of control, and both Danny Phantom and the building's security system designed by the father of Valerie Gray, a rich and popular yet less-than-friendly girl from school, proves unable to stop the ghost dog from destroying the lab. As Valerie's life turns upside down because of Danny Phantom, a "generous benefactor" (revealed to be Vlad Masters/Vlad Plasmius himself) helps Valerie exact revenge on Danny Phantom by turning her into a professional ghost hunter.

A recently popular singer named Ember McLain magically enchants and charms teenage audiences with her hypnotic song. When Danny challenges her, she musically hypnotizes him with a "love song." Now infatuated with Sam, Danny cannot focus on Ember and Sam must find a way to break his heart to get him fighting fit again.

Danny and Tucker become obsessed with an online game. As a result, Danny does not get enough sleep and fails a test that accounts for 25% of their marks. Mr. Lancer decides to give him another chance by letting him retake his test, but when Technus escapes and tries to take over the world by using his ghost powers in the game, Danny must pass his test quickly. After studying with Mr. Lancer and taking the test again, he manages to pass with a 91% and returns to the game. In order to defeat Technus, he decides to use his ghost powers in the game, too, and he quickly catches up with Sam and Tucker in the game. The three of them successfully trap Technus in a glitch in the game before Mr. Lancer stops them in his own online game.

When he catches Danny and Dash fighting at school, Mr. Lancer offers them a chance to avoid detention by competing in a haunted house contest instead of giving them detention with Danny and Dash making a bet on who will win. When Danny feels he is losing, he steals the sword of the Fright Knight, the ghost spirit of Halloween, in an attempt to make his haunted house scarier. However, danger arises when the Fright Knight awakens and terrorizes Amity Park.

Guest star: Michael Dorn as Fright Knight

Jazz falls for a biker named Johnny 13, and he tries to convince her to go steady with him swiftly. Unbeknownst to her, he is a ghost planning to use her body to contain the spirit of his girlfriend, Kitty. He nearly succeeds, but Danny stops him after becoming suspicious of Jazz's new boyfriend and sends him back to the Ghost Zone. Meanwhile, Tucker tries to change his image and ends up being labelled "Bad Luck Tuck," unknowingly being the inadvertent target of Johnny's bad luck Shadow.

Guest stars: William Baldwin as Johnny 13 and Chynna Phillips as Kitty

The town of Amity Park is thrown into chaos by the town's first mass invasion of ghosts. It's all part of the plan by Ghost Zone's top sheriff, Walker, to capture and incarcerate Danny Phantom. At first Danny battles, then befriends, a hulking ghost named Wulf. Walker and his goons overshadow most of the influential people in Danny's city. While eluding constant attacks from his ghost-fighting parents, Danny defeats Walker and restores calm in the city. However, Walker's actions and lies damage Danny's reputation in the public sphere, and Danny earns the title of "Public Ghost Enemy #1" in the process.

When Paulina sees Danny transform into his ghostly alter-ego, he fears that she will tell everyone, but not only does Paulina agree to keep Danny's secret, she becomes his girlfriend! Danny does not know Kitty (Johnny 13's girlfriend) has overshadowed Paulina in an attempt to make Johnny jealous after their fight. If Danny ruins Kitty's plans by turning her down, she will, as Paulina, tell the entire town that he is the Ghost Boy.

Guest stars: William Baldwin as Johnny 13 and Chynna Phillips as Kitty

In an attempt to bond with her distant son, Maddie takes Danny to a science symposium in Florida. However, the symposium proves a ruse by Vlad Masters to convince Danny and Maddie to stay with him and abandon Jack. Vlad also launches a ghost attack on Fenton Works, hoping to eliminate Jack. Meanwhile, Jack tries to bond with Jazz, who claims she wants nothing to do with ghosts but turns out to be a great ghost hunter after all.

Guest star: Martin Mull as Vlad

Danny and Valerie are forced to work together by watching a child-like flour sack for health class, but neither of them demonstrate willingness to help the other. After watching both Danny Phantom and the ghost hunter (Valerie) fighting, Skulker wonders which one is a more worthy prize. He handcuffs them together on his island and hunts them, holding the sack as ransom.

Note: Skulker is now voiced by Kevin Michael Richardson for the remainder of the series.

When Vlad's Ghost Portal (as well as his mansion) is destroyed, he places a million dollar mark to hunt down the legendary ghost boy, Danny Phantom, so he can sneakily try and steal the Fenton Portal. Many hired ghost hunters are parodies of other mystery shows, as Men in Black and Scooby-Doo are paralleled as teams bent on capturing Danny for Vlad.

Guest star: Martin Mull as Vlad

Ringmaster Freakshow arrives at Amity Park with his attraction, "Circus Gothica." His family heirloom, a ghost hypnotic, prompts Danny to join his circus and do his evil bidding.

Guest star: Jon Cryer as Freakshow

Danny and Sam get into a fight and Sam wishes she never met him, prompting Desiree to return and grant her wish, leaving Sam to witness a world without Danny Phantom.

Guest Star: Peri Gilpin as Desiree

Ghost bugs invade every kid in Casper High causing them to exhibit ghostly powers that go awry. When they are all sent to the local hospital for quarantine, Danny and Tucker (who has a case of nosocomephobia) investigate the matters behind this.

Danny encounters a bratty ghost-pirate boy named Youngblood, who has teamed up with the siren-like ghost girl Ember, to kidnap all the adults in Amity Park via Ember's hypnotically enchanted music.

Guest star: Taylor Lautner as Youngblood

Vlad Plasmius places the entire town of Amity Park in jeopardy when he accidentally releases the evil Ghost King, Pariah Dark, who invades both the ghost and mortal worlds. Even worse, all of the Ghost Zone residents flee their homes out of fear of the Ghost King and his armies, and Vlad is hiding out from the Ghost King in the Fenton Household. In order to combat this growing threat, Danny must team up with Vlad and several other foes to work side by side to stop the King of All Ghosts. Meanwhile, Valerie also fights alongside Danny as she grows feelings for him as well In this episode, Danny Phantom verifies his ghost name to the people of Amity Park.

• This is 49 minutes longer, being two episodes combined.^[2]

Guest stars: Brian Cox as Pariah Dark, Michael Dorn as The Fright Knight, Peter MacNicol as Sidney Poindexter and Martin Mull as Vlad Masters

Danny desires a separation between his fun and superhero lives. Using the Fenton Ghostcatcher, Danny splits himself in half and attempts to defeat Technus while spending time with Sam and Tucker.

As Youngblood continues to torment Danny, appearing as if Danny is fighting an invisible enemy and going crazy, Jazz decides a Fenton family vacation with no ghost hunting is the solution.

Guest Star: Taylor Lautner as Youngblood

Danny is desperate to pass a standardized test called the C.A.T. After a fight with a ghost from the future sent by the mysterious Clockwork puts the answers to the C.A.T. in his hands, he decides to cheat in hopes of securing an easy pass to a great future. After fighting another ghost from the future, he, Sam, and Tucker discover that Danny cheating leads to a horrible future where after the death of his family and friends, Danny grows up to be Dark Danny, the evilest and most powerful ghost on the planet who terrorizes the world. Upon discovering Clockwork's interference, Dark Danny tries to make sure Danny's horrible future comes to pass by trapping Danny in his timeline, while he returns to 14 year old Danny's time. To save his friends, family, and future, Danny must escape back to his timeline with the help of the future version of Vlad (who is indirectly responsible for Dark Danny's creation), and battle the evil Dark Danny to save his family, friends, future, and himself, with the help of a mysterious ghost named Clockwork. At the end of the episode, Danny finds out Jazz knows he is part ghost.

• This is 49 minutes longer, being two episodes combined.^[3]

Guest stars: Eric Roberts as Dark Danny/Dan Phantom, David Carradine as Clockwork and Martin Mull as Vlad Masters of the future

Thanks to his parents constant fighting over Santa's existence and subsequently causing chaos during Christmas, Danny has become a real Grinch when it comes to the holidays. But it gets a lot harder when he accidentally destroys the Ghost Writer's newly-finished Christmas-based story and refuses to apologize, causing the Ghost Writer to trap him in another story to teach him a lesson in Christmas spirit.

Guest star: Will Arnett as the Ghost Writer

Now that Jazz is a member of "Team Phantom," she tries her hardest to help Danny capture ghosts but often accidentally hinders his success. When her determination to help leads her to hack into Danny's computer, he cannot take it anymore and tells her she’s a "lousy ghost hunter, an overbearing sister and an annoying, obnoxious know-it-all who has no respect for her brother's privacy," all in front of eavesdropping schoolmates. Jazz runs off to Vlad Masters with a plan.

Danny and Valerie's budding romance comes full-bloom when the two start dating, making Sam extremely jealous. Technus pushes the romance to keep Danny busy and enable his next technological plan for world conquest.

Jack's newest invention accidentally shrinks both Danny and Dash, as well as Skulker, literally down to size. Because of this, Danny's powers slowly start to short out. He must make his way to the invention and make himself back to normal size before his secret is exposed to Dash.

To show how "dumb and pointless" they really are, Sam signs up for a beauty pageant, in which Danny serves as the judge due to being the perfect "common, average and bland boy". Little do either one of them realize this is all a plot from Dora the Dragon Ghost to find a wife for her arrogant elder brother, Prince Aragon.

Note: Beginning with this episode, Princess Dora is now voiced by Susanne Blakeslee, and Star is now voiced by Tara Strong for the remainder of the series.

Tucker runs for student council president and feels his voice goes unheard. But on a field trip to the museum, the ancient ghost Hotep-Ra recognizes him as a long lost pharaoh. Tucker finally feels listened to, but his glory consumes him and he sends Casper High back to an ancient Egypt-like place. Will Danny be able to stop a possessed Tucker or will all be lost?

An Ecto-Acne-ridden Vlad infects Tucker and Sam and forces Danny to help find a cure. Rather than help his foe, Danny travels through time to prevent the accident that caused Vlad to be half-ghost in the first place. This creates an alternate present where Vlad is married to Maddie, and Jack is the half-ghost.

Guest Star: David Carradine as Clockwork

Danny struggles to avoid treating his friends as sidekicks, as Sam and Tucker often take the blame or beating in Danny's ghostly adventures. After leaving them to clean up a golf course, Danny meets his "cousin" Danielle ("Dani") and learns that she herself has ghost powers. As the two half-ghosts battle an enemy ghost together, Dani dodges questions from her curious relative; she feigns weakness and pretends to faint into Danny's arms after the fight. The next day, another ghost attack silences Danny's further attempts to interrogate Dani. Left to take the blame for Danny's mess once again, Sam and Tucker begin to clean the cafeteria in detention, but when they witness Dani and Vlad fly off with an unconscious Danny, they flee detention and attempt to rescue their friend. Meanwhile, Danny discovers Dani is an imperfect female clone of himself created by none other than Vlad Plasmius. Will Danny's friends abandon their hard feelings and come to his aid yet again, or will Vlad finally obtain the DNA sample he needs to clone his ideal half-ghost son?

Guest star: AnnaSophia Robb as Danielle "Dani" Phantom

Sam falls head-over-heels for Gregor, a white-haired Hungarian exchange student who sweeps her off her feet, but a jealous Danny suspects he works for the Guys in White.

Summer vacation plans are put on hold when Freakshow kidnaps the parents of Danny and his friends. He demands them to locate the mystical Reality Gems: the Gem of Life, the Gem of Form, and the Gem of Fantasy for the Reality Gauntlet (with the Power Source) in exchange for their lives, but complications arise when Danny's ghostly secret is accidentally revealed to the entire world, including the Guys in White.

• This is 48 minutes longer, being two episodes combined.^[4]

Guest Star: Jon Cryer as Freakshow

Danny and Vlad's game of revenge starts off childish, but ends when Vlad runs for mayor of Amity Park and wins by possessing the voters. Now Danny must survive the grueling rules the billionaire-turned-politician has placed. In the end, Danny manages to force Vlad to undo his new rules by faking being blasted by him when he tries to make himself look good.

While trying to map out the Ghost Zone, Danny, Sam and Tucker befriend a ghost named Frostbite who gives them the "Infi-map" that can take the user to any location in the Ghost Zone. However, Vlad manages to steal it. It's up to Danny and friends to get it back, and they must travel through portals and time to defeat Plasmius.

As revenge on the men, Spectra, Kitty and Ember join forces and use their powers to make all males vanish from Amity Park. Sam, Jazz and Maddie must team up to undo the damage. Meanwhile, Danny and Jack deal with an unwelcome visit from Skulker during a father/son fishing trip.

Guest Stars: William Baldwin as Johnny 13 and Chynna Phillips as Kitty.

Looking to increase his popularity as mayor of Amity Park, Vlad frees "Vortex", a weather ghost, and enslaves him to convince the people that Vlad can control the weather. But Vlad loses control of Vortex, and a battle with Danny renders the boy with weather powers of his own, controlled by his temper.

A ghost with morphing abilities named Amorpho impersonates Danny Fenton as revenge for Danny Phantom's heroic exploits overshadowing the pranks he pulls be transforming into others and framing them, but both he and the actual Danny Phantom get locked in their forms by a Fenton Device, stuck in the cross holds of fame and madness from the citizens of Amity Park and two angry Fenton parents out for Danny Phantom himself.

A plant ghost named Undergrowth turns Amity Park into a literal jungle, in the process holding the citizens captive. He also kidnaps and brainwashes nature-loving Sam into being his "daughter" and the mother to his "children". Danny must save Amity Park while also trying to keep his newly developed cryokinetic abilities in check with the help of his friend Frostbite.

Guest star: Mark Hamill as Undergrowth.

The Fentons sell Fenton Works to the Guys in White who only plan to destroy the Ghost Zone (unaware that Earth will be destroyed too) with a missile, so Sam and Tucker must convince a now-snobbish Danny to stop the Guys the White.

Guest Star: Taylor Lautner as Youngblood.

The Box Ghost is frustrated that he isn’t taken seriously, so he steals Pandora's Box, unleashing its evil and successfully wreaking havoc on Amity Park. Too weak to fight, Danny's only option is to seek Pandora herself to stop the madness the Box Ghost caused.

Danny wakes up from a dream-powered machine, only to find the citizens of Amity Park all under the same deep sleep, thanks to the ghost of dreams Nocturn, who is sucking up their dreams to increase his energy. Danny must wake his friends and sister in order to stop the threat and end the living nightmare.

Danny, Sam, Tucker and their classmates go on a camping trip only to find that there are monsters lurking within the forest, kidnapping campers one by one, leaving Danny and Sam to investigate the matter by themselves and reunite with Wulf, whose appearance is linked with the disappearances.

Dani Phantom returns to Amity Park with a problem; she has trouble maintaining her body's stability, as she’s still incomplete. Meanwhile, Vlad sends Valerie to capture Dani so that he can use her Danny Phantom-themed DNA to make a much better clone of him. A Fenton invention ends up saving Dani after she turns into ectoplasm. In the end, Valerie finds out that Vlad Masters and Vlad Plasmius are one and the same and declares he is now one of her targets.

Note: In this episode, Dani Phantom is now voiced by Krista Swan.

Vlad concocts a plan to humiliate Danny into hiding by replacing him with a team of ghost-hunters he sponsors. After being humiliated and shown up by Vlad's team several times, Danny uses the Fenton Portal to remove his ghost half and decides to go back to a normal life, to the objection of his friends and Jazz. However, an giant asteroid that was blown out of orbit due to one of Vlad's failed schemes nicknamed the "Disasteroid", hurtles toward Earth, threatening not only Earth, but the Ghost Zone as well. Vlad sabotages the Fenton's plan to destroy the Disasteroid and he reveals his ghost half to the entire world in an attempt to gain world domination, but he fails when he discover the disasteroid is made from an element ghosts can't touch and flees into exile in space. Realizing the mistake he made losing his powers, Danny comes up with a plan to acquire a massive force of ghost energy to turn the Earth intangible so the Disasteroid will harmlessly pass through it. The first attempt to gather the ghosts needed fails and they attack Danny, but their combined ghost energy reawakens Danny's ghost half and he escapes. Danny Phantom announces his plan to the world and everyone works together to create a machine to turn the Earth intangible. Danny goes back into the Ghost Zone to try again to recruit the ghosts to help save the world. After Danny seemingly perishes, Jazz decides to tell her parents Danny's secret. However, Danny is revealed to have survived and convinced the ghosts to save Earth and themselves. Danny's plan works, saving the planet, and Danny reveals his secret to the world and is accepted with great enthusiasm. He gets a statue of his likeness erected in the capital city of every country in his honor and ends up finally dating Sam.

• This is 49 minutes longer, being two episodes combined.^[5]