Professor Simon Cross and his assistant, Elizabeth West, thought their time traveling days were over. That's before they stumble across a World War II photograph -- with missing time traveler, Evan Eldridge, injured and in desperate need of help.
They find Evan in 1942 London, ill and not quite sure what's happened. He remembers only one thing with crystal clarity -- the whereabouts of an artifact Hitler believes can win the war. That's information every Nazi spy in the country would kill to know.
As if saving Evan and surviving war-torn England weren't enough, the outcome of the war hinges on Simon and Elizabeth finding Evan's artifact before the Nazis do. But time is running out: for them, for London, for the world.