The year: 1943. Now there was to be no more retreat for Britain and her Allies. At last the war was to be carried into enemy territory. And from captured bases and makeshift harbours in North Africa, the Royal Navy's Special Force was to be the probe and the spearhead of the advance. To this unorthodox war came the corvette H. M. S. Thistle and her commanding officer, John Crispin.

Twenty-five years ago HMS Terrapin was part of a crack hunter/killer group in the Battle of the Atlantic. Now she is working out her last commission in the Gulf of Thailand. To Lieutenant-Commander Standish, the frigate seems to mark the end of his hopes of a career in the navy. Then a new captain arrives, a man driven by an old-fashioned, almost obsessive patriotism. And under his stubborn leadership, Standish and the crew discover a long-forgotten unity of purpose.

It was in 1943. On the Black Sea, the Russians were fighting a desperate battle to regain control. But the Russians’ one real weakness was on the water: whatever they did, the Germans did it better, and the daring hit-and-run tactics of the E-boats plagued them. At last the British agreed to send them a small flotilla of motor torpedo boats under the command of John Devane. Devane had been in the Navy since the outbreak of war.

Adriatic, 1940s... Curtis was the pro. He could steer a sub through a saloon and no one would notice. Duncan was the grumbler, more at home in the Aussie Outback than twenty fathoms under the Adriatic. Jervis was the spit-and-polish man, who knew the correct way to die. And George, the Cockney, was the toughest of them all. Four men in the Royal Navy’s smallest sub, preparing the way for history’s largest invasion.

In 1941, when she was turned into an armed merchant cruiser, the SS Benbecula was already old. Yet even she was needed to protect the vital Atlantic sea lanes. Commander Lindsay, her new captain, had to work desperately to mould the ship’s company - raw recruits and old-timers - into a fighting force. And better than anyone, Lindsay knew this could be his last command, his last chance.

Hong Kong, 1941... To the residents and defence forces of the Crown Colony of Hong Kong, the war in Europe remains remote. Even the massive build-up of Japanese forces on the Chinese border cannot dent their carefree optimism. Yet one man suspects the truth. Lieutenant-Commander Esmond Brooke, captain of HMS Serpent and a veteran of the cruel Atlantic, sees all too clearly the folly and incompetence of Hong Kong’s colonial administration. To Brooke, attack by Japan seems inevitable.

As captain of the crack Tribal Class destroyer HMS Hakka, Commander Graham Martineau must once again call from the ordinary seamen the ultimate in courage, and prepare to defend to the death vital convoys to Russia. No man and no ship is immortal.

HMS Royston, Coastal Forces Depot Ship, is mother ship to a battered, war-worn bunch of MTBs and MGBs. New on board is Sub-Lieutenant Royce: commissioned for three months, sea experience three months in an Asdic trawler, and aged 20. His commanding officer is Lieutenant Harston, aged 23.

His predecessor has been killed in action 48 hours earlier and is now hardly remembered. The crew are all young - some very young - but all old before their time....

The crack German cruiser Prinz Luitpold had always been lucky in battle. To the beleaguered army on the Baltic coast she was their one remaining symbol of hope. But it is the summer of 1944, and on every front the war is going badly for Germany. When the order comes to leave the Baltic to attack and destroy enemy shipping in the Atlantic, Kapitan zur See Dieter Hechler knows that once out in this vast killing ground it will only be a matter of time before the hunter becomes the hunted.

Indo-China 1941, and cruising somewhere off Saigon is the world’s largest, most dangerous submarine, the French Soufriere. The British navy must capture and use her in the defence of Singapore before she is used against them. For Commander Robert Ainslie it is the supreme challenge of his career.