Dark Tides (1998)

Sara and Ben, a fishing couple, stumble upon a buoy filled with half a million dollars while hauling in lobster traps. While Ben dreams of spending the money on indulgences, Sara views it as her escape from a dreary marriage and life in their coastal village. Determined to seize her freedom, she concocts a plot to eliminate Ben with the help of Don, his brother and her lover. However, their scheme unravels when the buoy’s owner shows up, alongside a group of ruthless mobsters and Kim, the mob boss's mistress, all eager for the cash.