James Franciscus, Elizabeth Shepherd, Ronald Allen, Reuven Bar-Yotam, Inigo Jackson. A daring plan to destroy the Nazi arsenal in Sicily is set in motion by an American commander (James Franciscus) serving under the British Royal Navy near Malta.

Tom Jeffords, an American serving as a lieutenant commander in the Royal Navy in 1942, is assigned to the blockaded island of Malta and ordered to create a plan to destroy a German arsenal in Augusta, Sicily, thus allowing the British to transport supplies to their troops in North Africa. Jeffords foresees the difficult nature of the operation, and he imposes strict discipline on the men in his command, an act which incurs their enmity. Despite Jeffords' warning, three men are killed in a reconnaissance mission. Comdr. Roger Ashurst, with whose estranged wife, Alison, Jeffords has become acquainted, doubts the success of Jeffords' plan, though he volunteers to command a German E-boat, a motor torpedo boat which the Germans call a "hell boat," and pilot it through German lines. The men destroy the arsenal, and Ashurst's bravery results in his being reunited with Alison.