The pain was gone in Chandler's chest. "Marta," he called.
"I'm afraid she's gone," the tall man said. "She and the entire Earth."
The short man pulled off his lab coat. "Over a thousand years ago."
"A thousand years?" Chandler's mind fumbled with the thought. "What's this all about?"
The tall man snapped a series of switches off. "You ask the same question every time."
"Every time?"
"We've sent you back three times now." The tall man traded his lab coat for a tunic. "Once you tried to X-bomb the Bering Strait Dam, but the crust shifted, wiping out the whole population. On the second time pass, you tried to tilt the Earth on its axis, but it was thrown out of orbit and plunged into the sun. This time—you still have your memories of that."
"Makes you wonder about fate," the short man said.
"But what am I?" Chandler sat up with an effort.
"You," explained the short man, "are a mind developed here in a Venus laboratory and sustained in a host body. You see, we can't send solid matter back in time, only waves moving at the speed of light. So we send your mind matrix to meld with Chandler's."