Upon entering Ebisugawa High School, Itsuki Noya goes to the 'Tenmon' club, believing it to be the astronomy club, and wishes to join. However, the club president, Kyōko Todayama, decides to first put Itsuki through some bizarre tests, which seemingly have nothing to do with astronomy. After the tests are more or less deemed worthless, Itsuki is made a member, saving the club from being abolished.

Episode Parody: Saint Seiya

Crybaby Hakata Kanamori is pushed around by Kyoko as she attempts to recruit people for the Tenmon club, the pressure of which soon causes her to delusionally dress up as a bunny. Kyoko soon decides to take advantage of Hakata's delusions and thrusts her into a magical girl battle to bring her back to the Tenmon club.

Episode Parody: Sailor Moon

A girl from another school becomes interested in the Tenmon club, although Kyoko is oddly hostile towards her. It is soon revealed she is Kyoko's younger sister, Izumiko, who was close with Kyoko before she ended up divulging in her delusions. Kyoko and Izumiko soon engage in a quiz battle, which is interrupted by the student council president, Yuka Iseda, forcing them to settle their score in another fashion.

Episode Parody: Ultraman Series

Club member Rikei Hiromatsu develops a fetish for being rubbed against by the club's cat mascot, Neko-sensei. She later runs into Izumiko again, prompting her to try to make amends with Kyoko. Meanwhile, the school is plagued with incidents of girls fainting, with Yuka threatening to abolish the Tenmon club if they can't prove they are innocent by the end of the day. Too lazy to investigate properly, Kyoko decides to accuse the first person she sees, which turns out to be Izumiko. However, the club's vice president, Hasumi Ōba, proves Izumiko's innocence whilst Rikei uses an army of cats to stop Yuka from abolishing the club. Afterwards, Izumiko joins the rest of the club in viewing the stars, where she notices a particular star, apparently known as the Death Star.

Episode Parody: Blue Comet SPT Layzner

Izumiko, who had long been searching for Itsuki, finally finds him, becoming shocked by the fact he was crossdressing the entire time. Itsuki explains how he was forced to crossdress as Kyoko only wanted girls to join the Tenmon club. Izumiko reveals she is the personal maid for Itsuki, who is the successor to the Noya group, often treating him like a toy. As Izumiko feuds against Kyoko over who gets to own Itsuki, she finds herself interesting in perfecting his crossdressing. Not willing to hand Itsuki over, Izumiko decides to transfer schools and join the Tenmon club.

Episode Parody: Fist of the North Star

Yuka, who is revealed to be a former member of the Tenmon club, comes to the clubroom to aboloish it. Hasumi invites Yuka to go stargazing with them before making a decision. Whilst waiting for it to get dark, the club holds a hero show whilst Hasumi and Yuka recall their childhood, in which they met an old lady who loves stargazing together. Later that night as Yuka is scared off by scary stories, she and Hasumi end up at the house where the old lady lived before she died. It is then revealed that the hero show was a part time job so the club could rent a telescopic camera to take a picture of the Rosette Nebula the old lady had always wanted to see.

Episode Parody: Metal Hero Series - mainly Space Sheriff Shaider

Kyoko impulsively decides to form a band, only to realise no one can actually play any instruments. As Kyoko remains undeterred and decides to shoot a PV to recruit musicians, the gang follow Neko-sensei and discover their teacher, Shōko Ōmori, is an obsessive stalker. Later, Kyoko arranged for Itsuki and Hakata to be locked in the clubroom in the hopes of gaining some 'interesting footage', but also to get Izumiko to get over Itsuki. It soon ends when Izumiko breaks them out after noticing Itsuki having headaches from stimulating situations. After being exposed to another bout of fanservice, Itsuki has a sudden change in personality, becoming his true self.

Episode Parody: K-on!

Without the constant medicine doses Izumiko had given him in the past, Itsuki becomes a confident fiend who can make women bow to him with his pheremones. As the others realise they need a drug to counter the effects of Itsuki's pheremones, Itsuki starts spreading his pheromones across the school, turning all the girls into loyal zombies. Kyoko develops a new batch of anti-pheremone and confronts Itsuki, but Izumiko stands in her way, allowing Itsuki to knock her out and escape with the anti-pheremone.

Episode Parody: MMR:Magazine Mystery Reportage

Kyoko and the others confront Itsuki, who transforms into a handsome adult form and uses a drug to transform Kyoko and Hakata into little girls with the intention of making them his loli maids. As Shōko manages to rescue them, Kyoko deduces that the same drug was used to keep Itsuki under control. Just as Itsuki arrives on the scene, his elder brother and Shōko's boyfriend briefly appears, turning Kyoko and Hakata back to normal before leaving. As Kyoko confronts Itsuki in a final showdown, she explains her research up until now was for the purpose of escaping the force engagement between her and Itsuki. As Itsuki overpower Kyoko, Izumiko stands against him, causing him to recall his true self and shoot himself with the antidote.

Episode Parody: Dragon Ball

With everything settled and Itsuki reverted to his normal form, the school prepares for a culture festival. As Kyoko questions Izumiko over why she likes Itsuki, she explains how she initially hated him when he transferred into her school, but warmed up to him as they started stargazing. Believing everything to be okay, Itsuki relieves Izumiko of her duty as his maid, which comes as a shock for her. Whilst following Neko-sensei the next day, Izumiko recalls how she first resisted against Itsuki's pheromone state. When Itsuki tried to jump in order to repent himself, Izumiko saved him but fell too, with Itsuki losing his memories of the incident protecting her, which he only regained following the battle with Kyoko. When Izumiko is put in trouble again after a 'telescope' tank dangles her over the edge of the building, Itsuki steps in to rescue her, confessing his love for her. They both fall, but are saved by the other club members. Afterwards, Kyoko arranged for her engagement to Itsuki to be cancelled so he can get together with Izumiko.

Episode Parody: Urusei Yatsura