Lonely widow Jamie Rowan (Katharine Hepburn) helps the war effort by marrying a military research scientist, Patrick Jamieson (Spencer Tracy), who has set up his lab in her house in Washington, D.C. Patrick has had all the worst of love and Jamie, all the best. They both believe that a marriage could be a success without love, as it reduces the chances of jealousy and bickering and all the other marital disadvantages. But as the film progresses, the inevitable happens as they begin to fall in love with each other.