The following edition of the text was used in the creation of this study guide: Waller-Bridge, Phoebe. Fleabag. Nick Hern Books, 2013.

Fleabag is a one-woman play featuring a 26-year-old woman, known only as Fleabag, living in London. While she interacts with different characters, only Fleabag is onstage, with other voices either pre-recorded or performed by the actor playing Fleabag switching roles.

The play opens with Fleabag at a job interview, running late and accidentally exposing her bra while taking off her sweater. The Male Voice interviewer criticizes her, and they exchange insults before she is asked to leave. Fleabag then directly addresses the audience, recounting a recent night where she ate pizza, watched 17 Again, Googled Barack Obama, and masturbated while watching porn, lying next to her boyfriend, Harry. The next morning, Harry left her a note saying he was leaving her. She explains that she and Harry break up frequently and that he always cleans the apartment before leaving. She reflects on her obsession with being desired more than sex itself and heads off to work at her guinea pig-themed café.

On her way to work, Fleabag notices a man staring at her but overhears him muttering "Walk of shame" (14) as he passes. She then tells the audience about her best friend Boo, who died after stepping into traffic in an attempt to upset her boyfriend, who she had just found out had slept with someone else. Boo didn't intend to die but caused an accident that killed three people, including herself. At the café, Fleabag briefly interacts with a customer, Joe, who seems down. Uncomfortable with his vulnerability, she busies herself with cleaning. Later, on the tube, she exchanges smiles with a stranger (referred to as Tube Rodent) and gives him her number, though she criticizes his appearance.

Fleabag meets her sister Claire at a feminist lecture series, a gift from their dad after their mother's death. Fleabag resents their dad's quick remarriage to their godmother. She shares her café's financial troubles and Claire offers her £5,000 to save it. Claire also plans to take a new job in Finland, despite her husband Martin's objections. Fleabag reveals that Martin made a pass at her last Christmas. During the lecture, both sisters awkwardly raise their hands when asked if they'd trade five years of life for the perfect body. Afterward, Fleabag texts Tube Rodent for a drink but criticizes him throughout the evening. Later, she suggests going to either of their places, but he declines, saying he wants to take things slow. Angry, Fleabag insults him and storms off.

At a tube station, Fleabag helps a drunk woman, Drunk Girl, get home but briefly tries to convince her to come home with her instead. Afterward, Fleabag recalls Boo singing a song to her. Drunk and emotional, she visits her dad, admitting her fear of being a bad person. He sends her home in a taxi with a £20 note. Fleabag then remembers meeting a ginger-haired man at a festival after Boo’s death. He helped her to her tent, but she was disappointed he didn’t make a move. She texts him, and they meet up for sex. The next morning, his sincere thanks for the encounter discomforts her.

The next day, at the café, Joe shows Fleabag two ukuleles and suggests they learn a song for Hilary, the café’s guinea pig. Fleabag dismisses him and hides until he leaves. She recalls buying Hilary for Boo and how they started the guinea pig café. In the present, Fleabag worries about not hearing from Claire regarding the café’s lease renewal. She listens to Boo’s old voicemail, texts an apology and a nude photo to Tube Rodent, and recalls an ex who often requested explicit pictures.

After closing, Tube Rodent visits, and they have unsatisfying sex. During the encounter, Hilary escapes, and Tube Rodent, scared of rodents, kicks her. Fleabag checks on the injured guinea pig, listens to Boo’s voicemail again, and leaves for a pub. Outside the pub, she watches Joe performing onstage. Returning to her apartment, she realizes Harry had been there earlier. She spends the night watching porn and doesn’t sleep.

The morning the café lease is due, Fleabag visits Claire, who reveals she’s not taking the Finland job. Claire sides with her husband Martin, accusing Fleabag of making advances on him. Claire says she cannot trust Fleabag because Fleabag slept with Boo’s boyfriend. Fleabag insists it wasn’t her fault; Boo's boyfriend wanted her. At the café, Fleabag offers sex to Joe, but he refuses, saying he checks on her because he had been worried about her since Boo’s death. After Joe leaves, Fleabag finds Hilary still suffering and tearfully kills her.

The play returns to the job interview from the opening scene. Fleabag asks what the Male Voice found funny in her resumé, clarifying it was a guinea pig-themed café. Addressing the audience, Fleabag admits to hurting Boo and destroying the business, saying she only feels alive through sex and porn has distorted her self-worth. Back at the interview, the Male Voice discusses his own mistake involving a harassment complaint. Fleabag says everyone makes mistakes, making him laugh. They restart the interview, but she curses at him when he finds her resumé funny again.