After she is rejected by her unborn child's father, Helen boards a train, which crashes on the way to San Francisco. Surviving the accident, she is misidentifed for another prenant woman who was also on board and did died in the accident. The Harkness Family, having never seen their new daughter-in-law, believe Helen to be the wife of their son who had also died in the crash. Seeing better oppertunities for her son with this family Helen plays along and assumes this woman's identify. The family believing her lapses in memory due to the aftermath of the accident. Things work out alright for the first few years, and just as Helen is finding herself falling in love with her brother-in-law, the child's real father shows up, and starts blackmailing her. Adapted from the novel I Married A Dead Man by Cornell Woolrich and starring Barbara Stanwyck.