Set in the early '60s, best friends and neighbors Alice (Chastain) and Celine (Hathaway) both live an idyllic traditional lifestyle with manicured lawns, successful husbands, and sons of the same age. Life's perfect harmony is suddenly shattered after a tragic accident. Guilt, suspicion and paranoia combine to unravel their sisterly bond and a psychological battle of wills begins as the maternal instinct reveals it's darker side.