David and Ann Smith are a young couple living in Manhattan who have made a commitment to never leave each other during a fight. They have had to remain together for long periods of time in the past, including eight days on one occasion and three days on another, due to their inability to resolve their arguments. When their most recent fight comes to an end, Ann asks David at breakfast if he would marry her again if he had the chance. David, who loves Ann deeply, replies jokingly that he would not.
That morning, David is visited at his office by a man who tells him that the Smiths are not legally married due to a technicality. Unaware that the man also spoke with Ann, David returns home that evening. Ann, remembering her husband's comment at breakfast, hopes that he will propose to her again now that they are not technically married.
The Smiths try to rekindle their courtship by going out to dinner at an Italian restaurant that they used to frequent, but the evening does not go well. When they return home, Ann believes that David has no intention of making their marriage official and locks him out of the bedroom, taking her maiden name. David moves into his club.
David's legal partner, Jeff Custer, hopes to marry Ann now that the Smiths have separated. However, David is determined to win Ann back and follows her and Custer to a winter resort at Lake Placid. When he shows her that he truly loves her, Ann agrees to reconcile with him.