In Reading, Pennsylvania, former high school basketball star Harry “Rabbit” Angstrom is dissatisfied with both his failure to find a career and with his loveless marriage to Janice, an alcoholic who is pregnant with a child neither of them wants. Following an argument with Janice, Rabbit looks up his old basketball coach Marty Tothero, who is now living in squalor. Marty decides that Rabbit needs a woman, and he introduces him to Ruth, a part-time prostitute. When Rabbit moves in with Ruth, Jack Eccles, the family minister, tries to persuade him to return to his wife, but Rabbit refuses.
Eventually, Rabbit also becomes disenchanted with Ruth, and when Janice has her baby, Rabbit goes to the hospital and effects a reconciliation. For a time, they live in relative harmony, but Janice’s insistence on a less active sex life leads to bitterness, and Rabbit again takes off. Janice resumes her solitary drinking, this time with tragic results; while in a drunken stupor, she accidentally drowns the baby. Learning of his child’s death, Rabbit returns home and finds that everyone holds him responsible.
At the funeral, Rabbit responds to his parents’ and in-laws’ accusing glances by screaming his innocence. Fleeing from the cemetery, he goes to Ruth’s apartment; but Ruth, who is now pregnant with his child, refuses to let him in unless he agrees to divorce Janice and marry her. Although he promises to do so, Rabbit is still unable to make a commitment to anyone and runs away again.