I WANT YOU BACK*CUT TO THE CHASE*
NOTE: This spoiler was submitted by Jeremy
The film starts as a couple, Emma (Jenny Slate) and Noah (Scott Eastwood), are out having lunch together. Noah tells Emma that he wants to break up with her because he doesn’t feel she is mature enough. Meanwhile, another couple, Peter (Charlie Day) and Anne (Gina Rodriguez), are at a birthday party for Anne’s nephew. Anne breaks up with Peter because she feels stuck with him and wishes she could have pursued an art career in Italy. Both Peter and Emma are left crying after getting dumped.
A short montage shows Peter and Anne/Emma and Noah in the early stages of their relationships, all looking very much in love, while cutting to the present day where Peter and Emma are destroying any keepsakes from their relationships. Emma in particular bothers her roommates, a college couple named Paul (Mason Gooding) and Lisa (Dylan Gelula).
Peter works for an agency that deals with nursing homes, but they are corrupt and are looking to cut costs by removing benefits or services for the elderly. During work, Peter checks his phone and finds that Anne is now dating the drama teacher from her school, Logan (Manny Jacinto). In the same building, Emma works as a receptionist for an orthodontist and is upset at seeing a teenage couple being in love. Making things worse for her is that Noah is already dating a new woman named Ginny (Clark Backo). Peter and Emma meet each other as they cry in the stairwell and explain their situations to one another. Peter offers Emma a cigarette until both realize they hate smoking.
Peter and Emma start hanging out as friends, calling themselves the “Sadness Sisters” due to their situations. They go drinking and visit second-run movie theaters to watch old movies like “Con Air”. Although they try to avoid checking in on their exes, Peter looks at Logan’s Instagram page to see a flirtatious interaction between him and Anne. Emma sees that Ginny owns her own pie shop and is successful. Realizing they miss their exes, they conspire to break up their new relationships, with Emma hoping to seduce Logan while Peter becomes friends with Noah to sabotage his relationship with Ginny.
Emma goes to the middle school where Anne and Logan work to volunteer for the school play. They are doing “Little Shop of Horrors”, directed by Logan. Emma pretends to have done the play already in the part of Audrey. Logan has her work on a papier-mache bust just as Anne comes in. Emma tries to be sexy with Logan, which prompts Anne to step in and introduce herself. While this goes on, Peter joins the gym where Noah works as a trainer and has him work as his own personal trainer. Peter asks him questions about Ginny, and then about Emma to try and get a read on Noah’s feelings.
Emma becomes more hands-on with the play and befriends a 12-year-old boy named Trevor (Luke David Blumm). She gives him a ride home when his dad forgets to, and he explains that he has been acting out as a result of his father cheating on his other father with another man. Emma offers him words of encouragement about life. Meanwhile, Peter and Noah start getting closer as friends, and Noah brings him to Ginny’s pie shop to meet her and sample her keto quiche. The two then make plans to attend a nightclub so Noah can help Peter meet other women.
Peter and Emma hang out again, and Emma notices how good Peter is with the elderly. He expresses his desire to open up his own nursing home and run it his way so that the people who live there have the best care in the world. They comment on how Emma said Peter is someone who one could fall in love with after a few years, but she says those are the best kind of people, because she likes a “slow burn” type of love and wants an “airplane oxygen mask” person, as in, someone who would apply her oxygen mask to her before himself during an emergency, even though Peter notes it would be easier to help after applying your own mask.
At school, Logan asks Emma to fill in for the actress playing Audrey for dress rehearsals. Despite her clear lack of knowledge of the play and its music, she puts on her costume and wig and manages to sing “Suddenly Seymour” with the actor playing Seymour quite well, with Logan telling her that he thought it was a deeply personal interpretation of Audrey’s character. Emma then joins Anne and Logan out for dinner, during which they agree to a threesome since Logan feels chemistry with Emma as well.
At the nightclub, Noah acts as Peter’s wingman until they end up hanging out with three women – Leighton (Isabel May), Chloe (Giselle Torres), and Taylor (Quinn Cooke). Noah accidentally pocket-dials Emma and talks to her briefly, leaving her disappointed because she thought he really wanted to talk to her. The girls invite Peter and Noah back to their house. Noah almost declines because he worries he might cheat on Ginny, but Peter promises to keep him out of trouble. They end up partying with the girls until Leighton’s ex Jase (Pete Davidson) comes by with drugs in an attempt to win her back. He has the group jump off the balcony into the hot tub, with Peter going along with it as well. Peter then notices Leighton wearing a high school jersey and realizes she and her friends are teenagers. He gets Noah just before Leighton’s dad (Ben McKenzie) comes home and the two have to run from him. The guys then sit on a bench, relieved they didn’t go further with the girls, but it makes Noah have an epiphany that he wants to marry Ginny. Peter feels that he’s just screwed up.
Emma watches the school production of “Little Shop” before going along with the threesome. Meanwhile, Peter tries to sneak into Noah’s home to plant a condom wrapper to make it look like Noah was cheating, but he backs out at the last second and is forced to hide in a laundry hamper when he hears Noah coming home. Noah sets up rose petals before Ginny comes home so that he can propose to her and she accepts. They have sex three times while Peter remains hidden, and he only leaves when the two of them hop in the shower together.
Emma joins Anne and Logan at his apartment as they commence the threesome. Anne stalls because she is clearly uncomfortable until she finally realizes that she misses Peter, so she breaks up with Logan. Emma also leaves Logan high and dry when it’s clear that nothing is going to happen anymore. Anne goes to Peter’s place since she still had a key and she tells him she misses him. They go to bed together, but when Peter talks about his nursing home dream, Anne tells him he doesn’t have to do it for her, as she thinks he made all these changes just for her.
Now that Peter and Anne are back together, he tells Emma that they can’t hang out anymore so that Anne won’t know about their whole plan. Emma feels upset about it. She starts to make changes in her own life and moves out to get a place of her own, and she also makes plans to become a guidance counselor. Emma then receives an invitation to Noah and Ginny’s wedding. While out at dinner by herself, she runs into Logan, who offers her some words of advice, and he agrees to join her for the wedding.
The wedding party takes place on a boat, with Peter and Anne running into Emma and Logan. Emma is still mad at Peter for what he told her. During the service, Peter looks lovingly at Emma, realizing he might have made a mistake. He also takes notice when talking about the nursing home dream, and Anne lies and says that she always believed in Peter. During the reception, things come to a head when Peter tries to admit his feelings to Emma. The other four come together as this happens, leading Emma to confessing her and Peter’s scheme to everyone. Logan tells Emma she’s insane, Anne breaks up with Peter, and Ginny tells Noah to get Peter and Emma off the boat. Although Peter tries to explain himself to Noah, he just gets punched in the face.
The next morning, Peter talks to Anne. He says that he doesn’t regret the six years they spent together. Anne eventually admits the same. Later on, Emma runs into Noah, where they admit that they were never really compatible, and she just thought he was a good catch that she could settle down with. They part on good terms, but he does tell her to stay away from Ginny.
Peter and Emma find each other on the plane and are seated across from each other. The plane hits turbulence, and the oxygen masks drop. Peter gets up and puts on Emma’s mask first before his own, leading Emma to realize that Peter is her “oxygen mask person”. As the plane settles down, the two of them smile at each other.
Peter and Emma just got dumped by their significant others, Anne and Noah. To make things worse, both of them move on to new lovers, Logan and Ginny. Peter and Emma become friends and conspire to break up the new couples to win their exes back, with Emma planning to seduce Logan while Peter befriends Noah to get between him and Ginny.
Emma volunteers at Anne and Logan's middle school to help out with a production of "Little Shop of Horrors" that Logan is directing, and she endears herself to him, as well as a young troubled student named Trevor. Peter also becomes close friends with Noah, but their time spent together leads Noah to wanting to propose to Ginny, and Peter cannot bring himself to get between the two of them. Emma gets Logan and Anne to agree to a threesome, but it ends up making Anne uncomfortable and she runs back to Peter. Peter tells Emma they can't hang out anymore or Anne will find out about their plan, but he starts to realize that Anne never believed in him the way Emma did and he realizes he really loves Emma.
Noah invites everyone to his and Ginny's wedding, with Emma inviting Logan. As Peter tries to confess his love to Emma, but it leads to her confessing the scheme to Anne, Noah, Logan, and Ginny. Logan abandons Emma, Anne breaks up with Peter for good, and Noah ends his friendship with Peter.
Peter parts with Anne after they mutually agree that they don't regret their relationship, while Noah and Emma eventually reconcile after admitting they were never really compatible. Peter and Emma meet again on the plane, and she realizes he loves her after the plane hits turbulence and he applies her oxygen mask before putting on his own.