When divorced New York couple Phil and Ellen Gayley each buy a winter coat for their seven-year-old daughter Phillippa, known as "Flip," artist Phil chooses a fancy coat, while his ex-wife chooses a conservative one. Flip is about to move in with Ellen, having spent the last six months with her father. Although Ellen is still in love with Phil, she pretends that she has been seeing other men. Phil asks Ellen to dinner and tries to convince her that he has changed a great deal during their year apart. At dinner, Nancy Graham, a model who has been dating Phil, walks into the bar of Luigi's restaurant just after Ellen goes into the dining room, and, seeing Phil there, assumes that she will have dinner with him. Using various excuses, Phil tries to juggle the two women, but Ellen discovers him eating with Nancy and leaves the restaurant. On Christmas Eve, Phil, who is eager to see his daughter, dresses as Santa Claus and sneaks into Ellen's apartment. Ellen mistakes him for her divorce lawyer, Rex DeVallon, who had earlier agreed to play Santa. When he spots Rex in another room, Phil locks him in the bathroom, but eventually Ellen realizes that Phil is wearing the Santa outfit. A fight breaks out between Phil and Rex, and afterward Ellen insists that Phil stay away from Flip during her six months with the child. Phil counters by suggesting that the three of them go away together to a rural cabin in Connecticut that is owned by his friend, Jack Gordon. His plans are ruined when Jack, Jack's girl friend and Nancy arrive at his apartment, expecting to go to the cabin with Phil. Even though Phil had made these plans while drunk, Ellen is furious and returns home alone. Meanwhile, Flip has been corresponding with a Marine, pretending to be older than she is, and has sent him a picture of Ellen instead of one of herself. Flip arranges for Fenwick Lonkowski, the Marine, to come to lunch. Fenwick recognizes Ellen from the photo Flip sent and assumes that she has been his correspondent. Ellen then decides to get revenge on Phil by flirting with Fenwick in public, and when she insists that Fenwick stay at her house, Phil connives to get knocked out in order to have an excuse to stay as well. Together, Phil and Flip plot to get rid of Fenwick, but all their plans backfire. Finally, Phil tells Fenwick that Flip wrote the letters, and when Fenwick learns how much Flip wants her parents to reunite, he decides to help her. Fenwick takes Flip to Luigi's, and she refuses to return unless her parents make up. Ellen finally agrees to take Phil back, and Fenwick consoles himself with Luigi's hat check girl.
