When a newlywed couple decides to open their relationship to strangers, the wife quickly realizes her husband is a sadistic monster whose fetishes might destroy her.

Based on ReShonda Tate Billingsley's novel of the same name, The Secret She Kept, a successful magazine executive marries a driven lawyer, who's on the cusp of a major promotion, only to discover that his wife is severely bi-polar. The movie explores the meaning of love and the vow of "in sickness and in health."