Beth Cappadora is attending a high-school reunion in a crowded Chicago hotel when her three-year-old son, Ben, disappears. The loss tears through the family: Beth is consumed by grief and guilt, her husband Pat tries to hold their marriage together, and their older son Vincent carries a burden no child should face. Years pass without answers, until a neighbourhood boy arrives at the Cappadoras' door offering to mow the lawn. Beth recognizes something in him and discovers that the child, now called Sam, may be the son she lost. His return does not restore the past as simply as everyone hopes. Ben has grown up loving another family, and the Cappadoras must confront anger, divided loyalties and the painful question of where a child truly belongs.