Les Chiens de mer

New Yorkers, David Sanders (Nolte) and Gail Berke (Bissett) are enjoying a much-needed vacation; while diving one day they discover the sunken wreck of a WWII freighter and unearth a gold coin as well as a mysterious glass ampule. Excited, they believe their discovery could be a long lost treasure, but they soon learn that their most valuable discovery is actually an ampule of morphine, one of thousands left behind on the medical supply ship. This discovery leads them into the hands of Henry Cloche (Louis Gossett Jr.), an extremely dangerous and powerful Haitian drug dealer who will stop at nothing to unearth the dangerous treasure. With the help of Romer Treece (Robert Shaw), an old treasure hunter, David and Gail soon realize that they have made a much more important discovery than the morphine and set out to keep their actual treasure a secret. (official distributor synopsis)