Lily (Alyson Hannigan) takes Robin (Cobie Smulders) over to her apartment (which she herself has not been to in three months) while they are out, only to find that it has become a Chinese restaurant called Madame Chew's House of Dumplings, decorated with her belongings. They are told by the hostess (who recognizes Lily from the photos she left) that the landlady died and Lily didn't have a written lease. Lily and Robin immediately head over to Ted (Josh Radnor) and Marshall's (Jason Segel) apartment to explain the situation, and Ted tells Lily that she is welcome to live with them, since she practically already does. Barney (Neil Patrick Harris) warns Ted that things will change with Lily officially living at the apartment, and that eventually they will force Ted out. Ted does not believe him, but after he finds "Shocky" (his very old coffee pot that always gave him an electrical jolt) in the garbage and replaced by Lily's coffee pot, he begins to think Barney is right. He feels even more threatened when Marshall tells him he wants to hang Lily's painting where the two swords hang. In order to try to reclaim his territory, Ted begins to label all of his food and then orders a life-sized English phone booth for the apartment. He begins to argue with Marshall about who should get the apartment, which leads to a duel with the swords that hung on the wall. Events become tragic when a coffee table collapses under Marshall's weight, and he stumbles backward and runs Lily through the shoulder. After she is patched up at the hospital, Lily tells them that she does not want to live there once she and Marshall are married because it is a "guy's apartment."
Meanwhile, Barney has hit upon a revolutionary idea in the dating world: The Lemon Law. Similar in nature to lemon laws for used cars, Barney's new lemon law for dating gives a person five minutes to decide if the date will go on for the rest of the night or not. They can call the date off for any reason in the first five minutes, avoiding bad dates. Robin argues that it takes longer for people to get to know each other, so Barney challenges her by setting her up with a nerdy guy obsessed with Star Trek. Barney calls her to try to get her to use the lemon law, but she refuses. The guy assumes it was a fake call, and she tells him that she would never do that. Only a few minutes later, she gets a real call from the hospital telling her that Marshall has accidentally stabbed Lily, and leaves. At the hospital Barney reveals that his lemon law is now "a thing," as he had just been "lemon-lawed" by a girl earlier that night. Once Lily is released from the hospital, they go eat Chinese dumplings at the restaurant in Lily's old apartment.