Meena lives with her father in a lighthouse perched atop an endless sea. Ever since her mother died in a shipwreck when she was little, she has been forbidden to go into the water. One day when her father goes missing during one of his dives, she has to venture deep into the sea to rescue him. However, the monsters that lurk beneath the surface cannot all be seen. Meena must face her past and fraught relationship with her father if she wants to survive.