Reactionary enemy regimes have brutally taken command in South Africa and Germany. U.S. and European shipping lanes are suddenly under attack. World War is at hand -- and for the ruthless Berlin–Boer Axis, the devastating weapons of choice will be tactical nukes used at sea.

The Voortrekker, a deep-diving state-of-the-art German submarine, is on the prowl, carrying more onboard firepower than many of the world's nations possess -- and the crippled sub USS Challenger is the only weapon in America's arsenal that can match up with the silent killer. But the nation's last hope is in dry dock -- and Captain Jeffrey Fuller, Challenger's brilliant, driven skipper, must get his damaged boat back in action weeks before it is battle-ready. Fuller has faced Voortrekker in the past and, unlike so many others, he survived. This time, however, the fight will take place in waters far too deep for a normal sub to withstand. And this time the prize will be America.

Later that day

Bachelor Officers Quarters,
Naval Submarine Base, New London, Connecticut

Outside the window, in the post-midnight pitch-blackness, the freezing wind howled and moaned. The wind slashed at the leafless trees on the slope that led down to the river. Now and then, sleet pattered the pane, the tail end of a strong nor'easter that had dumped a foot of snow. Inside the room, a candle glowed in one corner. The ancient steam-heat radiator hissed and dripped. Ilse Reebeck looked down at Jeffrey Fuller. "Do you want me to get off now?"

He met her gaze, with that slightly out-of-focus look in his eyes he always got right after making love. Jeffrey nodded, too sated to speak. Ilse felt him watch her intently as she left the bed. He stayed fully under the covers -- she'd noticed since they'd first become intimate on New Year's Eve that he was strangely shy with her about his body, well endowed as he was with muscles and dark curly hair and the scars of an honorable war wound. Ilse was proud of her figure -- she gave Jeffrey a last quick profile view and blew out the candle.

She got back in bed in the dark and put one arm across his chest and tried to fall asleep. It was good to lose herself in sex with Jeffrey Fuller, and tune out the rest of the world, but as the immediate ardor subsided she felt sad. Her family was dead, for resisting the old-line Boer takeover, her whole country in enemy hands. She'd been in pitched battle twice behind enemy lines, during tactical nuclear war, and killed and watched teammates be killed. The war was far from over, quite possibly unwinnable. Even the escape of sleep was a mixed blessing, because sleep brought on the nightmares. Nightmares of combat flashbacks, of hurling grenades and bayonet charges and incoming main battle tank ire. Nightmares of relatives hanging. Nightmares of reunions with friends who were decomposed corpses.

If she hadnt been at a marine biology conference in the U.S. when the war broke out, Ilse might well be dead now too, strung up with the rest of them.

The radiator stopped hissing. Jeffrey reached over Ilse for the batterypowered alarm dock on his bedstand. His elbow rubbed her left nipple. "Sorry," he said, but she thought it an odd thing to apologize for, just after making love.

"Zero one hundred," he said. "Right on schedule."

Wartime energy conservation, Ilse thought. The heat was turned off in all base housing every night at one until five in the morning, along with hot water and power.

"Typical U.S. Navy," she said out loud. "If anything, always prompt." Ilse wasn't sure herself whether she meant to be sarcastic. It just came out. Jeffrey didn't respond. He rolled on his side and she rolled on her side so he could press himself against her in a hug ...

"You should go back to your room now."

Ilse stirred. She realized she'd fallen asleep like this and a few minutes must have passed.

"No" she told Jeffrey. "I want to stay." The bed was designed for one person, but they were both so used to sleeping on narrow racks in a submarine, the mattress seemed spacious in contrast.

"We have classes in the morning."

Also typical Jeffrey, always thinking ahead, making his plans and his schedules. Must do this, mustn't do that ... The naval officer in him never really shut down, or turned off or whatever, to simply let him be a person. Even six weeks after they'd both been permanently detached from USS Challenger -- and were rested now from the rigors of their Germany raid, when Jeffrey was acting captain -- he still ran himself with military precision out of sheer habit. He was taking the Prospective Commanding Officers course, and she was going through...

JOE BUFF is a member of the U.S. Naval Institute and a Life Member of the Naval Submarine League, the Navy League of the United States, and the Fellows of the Naval War College. Highly regarded for his technical knowledge, he is considered an expert in the field of submarines, and two of his nonfiction articles about future submarine technology have won Annual Literary Awards from the Naval Submarine League. In addition to Crush Depth and his newest novel of submarine warfare, Tidal Rip, he is the author of the highly regarded adventure novels Thunder in the Deep and Deep Sound Channel. Mr. Buff lives with his wife in Dutchess County, New York. Visit his website at www.joebuff.com.