Well, he hasn't come yet, sir, he's more than a bit late tonight.

--London Porter to Ernie Pyle, referring to the German Bombers

London--26 October 1940

By noon Michael and Merope still hadn't returned from Stepney, and Polly was beginning to get really worried. Stepney was less than an hour away by train. There was no way it could take Merope and Michael--correction, Eileen and Mike; she had to remember to call them by their cover names--no way it could take them six hours to go fetch Eileen's belongings from Mrs. Willett's and come back to Oxford Street. What if there'd been a raid and something had happened to them? The East End was the most dangerous part of London.

There weren't any daytime raids on the twenty-sixth; she thought. But there weren't supposed to have been five fatalities at Padgett's either. If Mike was right, and he had altered events by saving the soldier Hardy at Dunkirk, anything was possible. The space-time continuum was a chaotic system, in which even a minuscule action could have an enormous effect.

But two additional fatalities--and civilians, at that--could scarcely have changed the course of the war, even in a chaotic system. Thirty thousand civilians had been killed in the Blitz and nine thousand in the V-1 and V-2 attacks, and fifty million people had died in the war.

And you know he didn't lose the war, Polly thought. And historians have been traveling to the past for more than forty years. If they'd been capable of altering events, they'd have done it long before this. Mr. Dunworthy had been in the Blitz and the French Revolution and even the Black Death, and his historians had observed wars and coronations and coups all across history, and ther...