A former World War II submarine captain and his friend turn to smuggling when a former crew member lays out a plan to retrieve some hidden diamonds. Geoffrey (Richard Johnson) and his sidekick David (
Roy Dotrice) listen to Riker (
Jeremy Kemp) as he tells of the hidden treasure near the Skeleton Coast of Africa. Julie (
Honor Blackman) is the passenger whose late husband supposedly hid the diamonds. With a dim-witted German named Johann (
Peter Vaughan) as their guide, the crew battle fierce storms and underwater danger as they make the treacherous trek to collect the missing diamonds in this action adventure. ~ Dan Pavlides, All Movie Guide