Mild-mannered Henry Limpet (Don Knotts) longs to serve his country during World War II, but he can't pass the Navy's admissions physical. Classified as "4-F" -- too small and too weak to be a soldier - Henry takes a trip to Coney Island where a magical wish changes Henry Limpet from a little fish in a big pond into...well, a fish! With a fin up on the enemy, Henry uses his new aquatic abilities to lead the Navy into battle as their ultimate secret weapon!
