Phoebe finds a photo with her mother's writing and tracks down a woman in Montauk who may know where her father is. Because of this, everyone heads to the beach with Phoebe for the weekend. Ross' girlfriend Bonnie, however, has to stay behind as she is working. At the beach house the gang discovers the floor has been completely covered in sand and Phoebe casually mentions that the massage client who loaned her the house mentioned there "might have said there was some flood damage." There's no source of entertainment, so the guys resort to playing "Strip Happy Days". Rachel tries to get Ross drunk, which what with her earlier attempt at getting Ross to paint his toenails, seems a pretty clear message for her to get back with him, which Monica notices. Rachel's plans, already interrupted by Phoebe's entrance earlier, are again interrupted with the sudden, nexpected arrival of Bonnie at the beach house.
Phoebe finds her namesake, Phoebe Abbott, who according to her mother Lily's writing, is her late parent's best friend. She seems to know Frank, Phoebe's father, but is reluctant to give Phoebe any more information about him. When Phoebe breaks in Abbott's house to look for information about Frank, she wakes Abbott up. Abbott finds Phoebe's thirst for knowledge uncanny and reveals a secret to her - she is, in fact, her birth mother.
At the house, Chandler keeps nagging Monica into considering him to be her boyfriend; Monica, however, can't find enough "boyfriend material" in Chandler to take the offer seriously. Meanwhile, Bonnie takes advantage of the now-clear weather to have a swim but is annoyed by the sand she has in her hair. Rachel takes the chance to suggest to Bonnie to shave her head, which Bonnie does, reducing her head to a round, shiny, hairless dome. Everyone is shocked by Bonnie's new appearance, especially Ross. He asks for an explanation to this, and Bonnie reveals Rachel as to being behind the whole shave-the-head idea. Ross is angry at Rachel, but his anger dissolves into nothing when he learns that Rachel did this because she's still in love with him. The two kiss, but are interrupted by Joey and Chandler. The guys point out to him that it's his chance to get back together with Rachel; but Ross likes Bonnie too much to dismiss her in such a crude manner. The episode concludes with Ross climbing the stairs and then trying to decide whether to enter a door that will lead to Rachel's room, or a door that will lead to Bonnie's. As he opens one of the two doors without it being specified whose room he has entered, the screen fades to black.