Troubled by a past encounter early in his career, Royal Navy Lieutenant Commander Alec Weston soon became a respected, if intense, skipper. He was determined that his submarine, H.M.S. Undefeated, would live up to her name — therefore he pushed his crew and the vessel hard.

When ferrying a Special Boat Section assault team on a secret mission in the Mediterranean, Alec was faced with a tough decision that affected the lives of that Special Forces unit. Such was the burden of command…