During WW2, Italian Navy divers use underwater chariots to mine the keels of British warships, forcing the British to send underwater demolition expert Lionel Crabbe and his team to counter these enemy actions.

In the Mediterranean in 1941 the Italians start using underwater chariots to mine the undersides of allied ships. Explosives expert Lionel Crabbe arrives in Gibraltar to organise defenses, but finds only two British divers available to help him. Even more worrying, it seems likely that the Italians are secretly using neutral Spain across the bay as their key base.—Jeremy Perkins {J-26}

In the Mediterranean in 1941 the Italians start using underwater chariots to mine the undersides of allied ships. Explosives expert Lionel Crabbe arrives in Gibraltar to organize defenses, but finds only two British divers available to help him. Even more worrying, it seems likely that the Italians are secretly using neutral Spain across the bay as their key base.—Derek Dalmedo

Lt. Lionel Crabb, RNVR, is sent to the Royal Navy base at Gibraltar as Bomb and Mine Disposal Officer. Rather than simply dispose of unexploded mines and explosives he wants to locate enemy devices and protect the ships anchored in the harbour. He assembles a team of divers. Their greatest enemy is Italian frogmen riding "chariots" - human torpedoes. Recently two British battleships were severely damaged in Alexandria harbour and now they've shifted their attention to Gibraltar.—grantss