An old SF work involving an unusual sort of time travel.
Malcolm Lockridge is in jail when a strange woman, Storm Darroway, comes to him and offers a high-powered lawyer and private detectives to clear his name. All she wants in return is for him to take a job for her. Even at the time, he notices her unusual appearance -- unplaceable by ethnicitiy or race -- especially with the Anglo-Saxon name. His name cleared, he follows her directions to Denmark, where she spins him a story about retrieving a treasure left behind by Resistance members.
When they get there, they actually move through time -- down one of the title corridors, which have their own time and turn our time to a spacial dimension -- to a Denmark still in the neolithic age -- though elsewhere in the world they have reached the Bronze Age. She explains that she is a leader in one side of a time war. Her side, she explains, is trying to resist the other side's attempts to rationalize human life into machinery. But an actual war in their time would destory the earth, so they fight through time. While history is fixed, they can work through the gaps. She had been ambushed and stranded in his time, where she desperately needed a man to be safe in this era.
This story goes on, involving a native young woman who named Lockridge "Lynx", an invasion, an attempt to force an arranged marriage, traveling through time, a glimpse of the future Storm comes from, and a glimpse of the world past it. Lockridge finds himself crucial in a manner he had never expected.