Molly Murphy - now Molly Sullivan - is a year into her marriage, expecting her first child, and confined to the life of a housewife. She's restless and irritable in the heat of a 1904 New York summer. So when a letter arrives addressed to her old detective agency asking her to locate a missing Irish serving maid, Molly figures it couldn't hurt to ask around. On the same day, Molly learns that five babies have been kidnapped in the past month. Even when Daniel sends her away to stay with his mother, Molly cannot ignore these missing children.