Season 20 begins with Ben at the Bachelor Mansion. He meets with three former Bachelors Jason Mesnick, Sean Lowe and Chris Soules, who share advice on how to step into the role. Later that night, Ben greets twenty-six new bachelorettes at the mansion. Lauren B., a flight attendant, steps out on a limo and gives him a wing pin; Lauren R. stalks Ben on social media; Shushanna introduces herself to Ben in Russian; Leah catches a football; JoJo wears a unicorn head, which surprises Ben; Breanne presents a basket with bread; Mandi arrives with a huge "first impression rose" on her head; Izzy arrives wearing a onesie; Rachel rides in on a hoverboard; and Maegan brings her pet horse named Huey. Chris Harrison interrupts Ben's one-on-one time with the ladies as two former contestants, Amber and Becca, have come back to be part of the cast. Ben gives the first impression rose to Olivia. At the rose ceremony, Breanne, Izzy, Jessica, Laura, Lauren R., Maegan and Tiara are eliminated.

The first group date involves ten women participating in a "Bachelor High" competition at Verdugo Hills High School. The competition has five different challenges. Mandi is crowned "Homecoming Queen" after winning all of the challenges, but JoJo receives the group date rose. For his first one-on-one date of the season, Ben and Kevin Hart stop by the Mansion to pick up Caila. The trio travel around Los Angeles buying condoms and relaxing at a spa. Ben and Caila attend a concert with Amos Lee at the Regent theater and Ben gives her the date rose. The second group date involves Ben taking six women to a LoveLab facility at Azusa Pacific University for a scientific test using an electrocardiogram (ECG) sensor and electroencephalogram (EEG). Olivia receives the group date rose. At the rose ceremony, LB decides to leave, while Jackie, Mandi and Samantha are sent home.

Lauren B. gets the first one-on-one date for the week, which involves riding an airplane overlooking Southern California (including a view of the Mansion). Lauren B. receives a rose, and she and Ben end the night with a private stage by Lucy Angel. On the group date, twelve women go to Los Angeles Memorial Coliseum and meet Alex Morgan and Kelley O'Hara; they split into two teams--Stars and Stripes--and play soccer, with the winning team earning time with Ben at an after party and the losing team being sent home. Team Stripes wins and continues on to the after party, where Amber receives the group date rose. Jubilee gets the second one-on-one date, traveling to the Cal-A-Vie Health Spa Vista via helicopter with Ben. Over dinner, she shares her story, including how she was adopted. Ben gives Jubilee the rose. At the cocktail party, Ben tells the ladies he has received bad news from his family. Jubilee is very upset and Amber comforts her in the bathroom. Lace decided to leave the competition. At the rose ceremony, Jami and Shusanna are eliminated.

The fourteen ladies travel to Las Vegas, Nevada. JoJo gets the first one-on-one, which involves being whisked away on a helicopter ride to the Las Vegas Strip and watching spectacular fireworks. At the end of the night, Ben gave the rose to her. On the group date, ten ladies go to The Mirage and participate in an annual talent show hosted by Terry Fator. Notable acts include twins Emily and Haley excelling with Irish dance moves and Olivia popping out of a cake in a showgirl costume; after her performance, Olivia becomes embarrassed and upset. Lauren B. receives the group date rose. Along with her invitation for the second one-on-one date, Becca receives a package that proves to contain a wedding dress. Confused, she visits the Little White Wedding Chapel with Ben and talks to actual married couples about marriage. She receives the rose. Ben brings Emily and Haley to their house, where they meet with the twins' mom to discuss opportunity issues. Ben decides to eliminate Haley at this time. At the rose ceremony, Amber and Rachel are eliminated.

The eleven remaining ladies travel to Mexico City, Mexico. Amanda gets the first one-on-one date; Ben comes to the hotel early in the morning to take her to the ancient city of Teotihuacan for a morning scenic view and a picnic. They conclude the evening in the Santa Fe district and Amanda gets the rose. Nine ladies (Emily, Becca, JoJo, Leah, Jen, Olivia, Jubilee, Lauren B., and Caila) take Spanish language lessons at a local school, learning vocabulary so they can buy items to prepare an assigned Mexican recipe. The women are divided into six teams of two, with Olivia paired up with Ben; the other women are dismayed that she gets more time with Ben. Jubilee and Lauren B.'s dish is praised by the local chefs. Lauren B. and Ben are serenaded through the city, while Jubilee is sent home. Ben gives the group date rose to Olivia. Lauren H. gets the second one-on-date and goes to Pineda Covalin headquarters to take part in Mercedes-Benz Fashion Week. She and Ben join the show alongside professional models, and Lauren H. receives the rose. At the cocktail party, Olivia calls Amanda a "Teen Mom", sparking outrage among the other women. As the rose ceremony is about to start, Ben asks to speak to Olivia in private. The episode ends in a cliffhanger.

Beginning where the previous episode left off, Ben pulls Olivia aside to discuss the concerns other women in the house have raised to him; Olivia insists the women are overreacting and targeting her unfairly, and Ben believes her. They rejoin the others at the rose ceremony, where Jennifer is eliminated. The nine ladies travel to Exuma in The Bahamas. Caila gets the first one-on-one date for the week, which is her second one-on-one date this season; she and Ben take a deep sea fishing trip, and Ben gives her a rose. Six women (Lauren B., Leah, Amanda, Becca, JoJo, and Lauren H.) are selected for the group date, and Leah becomes very upset that she still has not received a one-on-one date while Caila has received two. They go to Pig Beach to swim with pigs, which none of the women enjoy. Throughout the date and the after party, the women voice their concerns to Ben that he seems to favor Lauren B. over them; Leah uses her time to talk about women in the house acting differently than they do around Ben, implying that Lauren B. is inauthentic around him. Amanda receives the group date rose. The next day, Leah visits Ben in his room to discuss their relationship and why she hasn't had a one-on-one date. Ben says their connection isn't strong enough and sends her home. Olivia and Emily are sent on a two-on-one date, traveling to an uninhabited private island. Ben has some one-on-one time with each of the ladies before giving the rose to Emily. Olivia is left behind on a wind-swept beach. At the rose ceremony, Lauren H. is sent home.

The remaining six ladies travel to Ben's hometown of Warsaw, Indiana, where Ben meets his parents at the restaurant. Lauren B. gets the first one-on-one date; Ben takes her on a private tour of the whole town, then playing basketball with a youth league and Indiana Pacers players Paul George and George Hill at Baker Youth Club. Lauren B. receives the rose and is guaranteed a hometown date. For the second one-on-one date, Ben takes JoJo to Wrigley Field in Chicago to play baseball by themselves; she and Ben wear matching "Mrs. Higgins" and "Mr. Higgins" uniforms. Their night concludes with dinner on center field, where Ben gives JoJo the rose. Caila, Amanda, and Becca go to a farm for a group date. Ben gives the group date rose to Amanda; they continue the evening with dinner at McDonald's and going to a carnival. Emily goes to Ben's house to meet with Ben's parents. They express concerns about her immaturity, stating they believe she is not ready to become a wife. Ben eliminates Emily. At the rose ceremony at the Old Kosciusko County Courthouse, Becca is sent home.

Ben travels to the hometowns of the final four ladies. Amanda's hometown date begins in Laguna Beach in Orange County, California; she brings her two daughters with her to spend time with Ben at the beach. Ben had written a storybook for Amanda's daughters and reads it to them. Lauren's hometown takes place in Portland, Oregon, where they explore Pioneer Square and the city's famous food trucks; she and Ben eat a traditional Georgian khachapuri pie and end the night at Multnomah Whiskey Library. Caila's hometown date takes place in Hudson, Ohio. They take a tour of her former high school and visit the toy factory where her dad works. Caila's family surprises the couple with a traditional Philippine food dinner. JoJo's hometown date in Dallas, Texas is off to a rocky start, with her finding an envelope and roses from her ex-boyfriend on her doorstep. Ben meets her family, including her brother, Ready for Love star Ben Patton. JoJo's brothers are unimpressed by Ben and accuse him of brainwashing JoJo; she attempts to calm down her brothers and confides in them that she's falling in love with Ben. At the rose ceremony, Amanda is sent home.

Ben and the final three ladies traveled to Ocho Rios in Jamaica for their overnight dates. Caila takes a ride on a wooden raft down the Martha Brae River, enjoys a riverside lunch of jerk chicken, and ends with a night of fireworks. Lauren B. travels to a preservation mission where they assist baby turtles. She tells Ben that she is in love with him, and he says he loves her too. They end the night watching reggae musicians on a bar stage. JoJo rides in a helicopter to a waterfall near Negril. She and Ben express that they are in love with one another, reflecting on the difficulties with her overprotective brothers during her hometown date. All three dates end in the Fantasy Suite. Caila goes to see Ben to share her feelings with him, proclaiming that she is in love with him; Ben admits that he is in love with his other two contestants and not with her, and he sends her home.

Seventeen of the twenty-six eliminated contestants attend the "Women Tell All" special, sitting in this particular order: Lace, Tiara, Amber, Jami, Izzy, Rachel, Jubilee, Shushanna, Jennifer, Lauren H., Leah, Olivia, Becca, Haley, Emily, Amanda and Caila. Several of the contestants talk about their lives after the show, notably Jubilee sharing that she has been promoted to Sergeant in the United States Army. Lace reveals a tattoo that a Bachelor fan has received in her honor, and Chris asks her to join the Bachelor in Paradise cast. Olivia recounts when she called Amanda a "Teen Mom" in the Bahamas and how she felt targeted throughout her time on the show. She gives Amanda a heartfelt apology. Caila explained her emotions when she told Ben she loved him and he didn't tell her he loved her back. Ben shows up to the ladies and finishes the show by stating that he is engaged to the winner and "would marry her tomorrow".

Both Lauren and JoJo meet Ben's parents (David and Amy) on a villa in Jamaica where they have spent time with Ben. Lauren's final date involves snuggling on a catamaran and a picnic on a beach. JoJo's final date involves swimming in the waterfalls. Ben reiterates that he has fallen in love with both Lauren and JoJo, and during their individual dates each woman sobs about the sacrifices they have made on the path to love. At the final rose ceremony, JoJo exits the first limo. She states how much she wants to be with him and how in love with him she is. Ben admits that he cannot propose to her, leaving her blindsided and heartbroken. Ben calls Lauren's dad to ask him for permission to propose to Lauren, and he gives Ben his blessing. Lauren arrives, they profess their love to each other and Ben kneels down on one knee and asks Lauren to marry him. She accepts and Ben asks, "Lauren, will you accept this rose?", with her answer being "Yes".

During The Women Tell All special, Ben stated that he would "marry (the winner) tomorrow", so Chris has arranged for both families and Ben's pastor to be on hand in case they actually want to get married on live TV. JoJo comes out first to see Ben for the first time since their breakup. Ben apologizes again for breaking her heart, saying he simply realized that he loved Lauren even more than he loved JoJo. Afterwards, Chris announces that JoJo will be the next Bachelorette. Then, Lauren comes out and she and Ben continue to profess their strong love for each other. They discuss her move from Southern California (Marina del Rey) to Denver, Colorado to be with Ben. In addition to Ben's pastor and their families, Jimmy Kimmel appears in the audience as well, making jokes about their overnight date from Week 9. They decide not to get married during the show, but Ben proposes to Lauren once again in front of the studio audience with their families present. They promise to marry soon.