December 1917: Germany opens the final, bitter round of the war with a new and deadly weapon in the struggle for the seas - the Vulcan. When she sails from Kiel Harbour, she is, to all appearances, a harmless merchant vessel. But her peaceful lines conceal a merciless firepower: guns, mines and torpedoes that can be brought into play instantly. The Vulcan is a commerce raider. And under crack commander Felix von Steiger, her mission is to bring chaos to the seaways. Her enemies have no idea what lies in store...