Pete Seltzer is introduced to Tillie Schlaine at a party. Her friends Gertrude and Burt are the hosts and attempting to fix her up.Pete is a confirmed bachelor with eccentric habits. When he isn't doing odd motivational research for a San Francisco firm, he plays ragtime piano, and makes bad puns. He periodically pops in and out of Tillie's life, going days without calling, but showing up spontaneously at her door. When they finally make love, he learns Tillie is a virgin.It appears Pete might still be seeing other women, but when he gets a promotion at work, Tillie announces it's time to get married. They do, then buy a house, and have a baby boy. Pete's affairs, however, apparently continue, Tillie even needing to discourage one of his young lovers at lunch.Years go by until one day, 9-year-old son Robbie is stricken with a fatal illness. Pete tries to shield the boy by keeping him in what Tillie calls "a world of nonsense", but the inevitable death destroys Tillie's religious faith, and ruptures their marriage.Tillie abstains from sex, while Pete turns to drink and takes an apartment. Tillie's depression is alleviated a bit by a friendship with Jimmy, who is gay, but willing to marry her if that would make Tillie happy. When she and Jimmy conspire to make Gertrude reveal her true age at long last, the result is a public brawl between the two women.Tillie ends up in a sanitarium. Her life has come to a standstill until Pete turns up one day. When she sees the way their son's death affects him, after his years hiding it, Tillie and Pete leave side by side.