Following an heroic part in the Second Battle of Narvik, Captain Barr puts the marines, his ship and certain captured enemy vessels to such good use that their exploits come to the notice of the First Lord of the Admiralty. Churchill sees how the 'Nishga's' exploits dovetail so well into his own fledgling tactic of 'Butcher and bolt'. He orders the new unit to carry out clandestine missions behind enemy lines. Already Churchill has seen that commando raids will be one of the few means by which a beleaguered Britain will be able to take the fight to the enemy. Soon Orca becomes an elite...