Based on a play by Philip Barry, a scientist and a widow get married to work together without romance, which naturally grows from friendship.
In Washington, Pat Jamieson (Spencer Tracy) needs a place to live and goes with drunk Quentin (Keenan Wynn) to the house of his cousin Jamie. Paul wants to use the basement. Edwina (Patricia Morison) comes in and quarrels with Quentin and Pat. Jamie (Katharine Hepburn) interviews Pat for a caretaker job, and he scares away an applicant. She learns that he is a scientist and hires him. She is a widow. At night Pat plays piano, and Jamie listens. He asks her to talk about herself. Pat says he had one love that did not work and wants no more. Jamie says her husband was wonderful, and she wants no one else either. When Pat urges her not to close herself off, she gets perturbed and tells him to leave. His lab equipment is brought in, and he says he is working on an oxygen mask. Jamie changes her mind and lets him stay while she goes away.
Kitty (Lucille Ball) comes in, meets Pat, and shows the house to Paul Carrell (Carl Esmond). Quentin tells Kitty that his engagement to Edwina is off. Pat knows Paul. Jamie says the house is not for rent. Jamie asks Pat about his work, understands it, and is helpful. She says why she likes Pat and asks if he wants to marry her for reasons other than love.
Pat and Jamie work together. Professor Grinza (Felix Bressart) arrives from Chicago and learns that Pat and Jamie got married that day. They do an experiment and urge Grinza to stay the night, but he leaves. Jamie and Pat say good night and retire to their own rooms. Jamie gets up for water, and Pat walks in his sleep to her bed. She finds him asleep and wakes him. Pat says he has somnambulism.
Pat and Jamie work in a Virginia house. Quentin sees Kitty, who is jealous of Edwina. Quentin says that Paul noticed no kissing between Pat and Jamie, and Quentin kisses Kitty. Paul tells Jamie that she does not love her husband. She says she and Pat are happy. Paul kisses her, and she tells him not to do that again. She says that she and Pat are in love.
Jamie joins Pat on a train to Chicago. At a hotel Pat buys flowers and gets a call from his past girlfriend Lila. Jamie celebrates her birthday with Pat in their room. She tells Pat to see Lila; but he gets upset, refuses, and goes for a walk. Pat tests the oxygen mask as Grinza observes. Pat returns home with a cake. Kitty comes in and says that Lila is at a party with Paul and Jamie. Pat goes with Kitty, and they see Quentin is in a sailor uniform. Kitty lets Quentin kiss her. Edwina sees them, but Quentin implies he wants to marry Kitty. Pat goes to Paul's room, but Jamie is not there. Paul goes home and pretends to sleep walk, but Jamie comes in and imitates Lila. Jamie and Pat talk about divorce, but neither wants it. Finally they embrace.
This comedy explores how two people who are not looking
for romance can find friendship in partnership that gradually
reawakens love.