Serenity

Baker Dill is a fishing boat captain living a quiet and sheltered life on an island off the coast of Florida. He spends his days leading tours off a tranquil, tropical enclave called Plymouth Island and is obsessed with catching "Justice", an evasive giant tuna.

One day, his ex-wife Karen tracks him down with a desperate plea for help. She begs Dill to save her and their young son from her new, violent husband, Frank, offering Dill $10 million to drop her husband into the ocean for the sharks to eat. She tells Dill that Frank will be arriving later in the week and that they have booked Dill for a fishing trip, the perfect opportunity for Dill to drop him overboard.