The Bayshore Club, a shop in a small coastal North American town, draws crowds with its astronomically priced mysterious oysters, guarded by a Bell family taboo: only married women may learn their secret. Ella, the shop owner's daughter, discovers her mother's jewelry embedded in oyster flesh and uncovers the horror: her parents breed demonic oysters using women's bodies. Her elder sister Luna, widowed under bizarre circumstances, is locked in the back kitchen by their parents, her keepsakes surfacing inside the shells one after another. As their mother's vitality fades, she pressures Ella to bring her boyfriend Daniel home to marry. Gentle-seeming Daniel secretly covets the trade's enormous profits and probes the back kitchen's secrets. Ella's call to police leads nowhere, and she is forced to register the marriage. When their mother suddenly falls critically ill, the family compels the newlyweds to stay overnight at the club—where the ancient curse of female sacrifice closes in. Ella must rescue Luna and shatter the ritual before she becomes the next harvest.
