Medical student Lucy, enduring domestic abuse, finds solace in a secret D/s relationship with a mysterious dom called "Daddy." New anatomy professor Ethan is stern and rigid, yet his voice matches Daddy's exactly, leaving her confused. When her gambler father sells her to the mafia to pay debts, Ethan rescues her at gunpoint and takes her in, and feelings grow. Lucy is coerced into an SM club auction; Ethan bids two million to save her, and they become intimate. After he uses his connections to save her dying mother, Lucy finally keeps her date—only to discover Ethan is the Daddy she has relied on for two years.