As he approached the room that had once been his office, he carefully planned what he would say to his successor. He would explain the accident first, of course. Then he would establish his identity beyond any possibility of doubt and request permission to use the two-way rig to return to his own time. The chief would probably be belligerent at first. But he’d quickly enough become curious, and finally amused at the chain of events that had ensnarled Mahler.

And, of course, he would make amends, after they had exchanged anecdotes about the job they both held at the same time across a wide gap of years. Mahler vowed that he would never again touch a time machine, once he got back. He would let others undertake the huge job of transmitting the jumpers back to their own eras.

Ht moved forward and broke the photoelectric beam. The door to the bureau chief’s office slid open. Behind the desk sat a tall, powerfully built man with hard gray eyes.

Me!

Through the dim plate of the spacesuit into which he had been stuffed, Mahler stared in stunned horror at the man behind the desk. It was impossible for him to doubt that he was gazing at Inflexible Mahler, the man who had sent four thousand men to the Moon, without exception, in the unbending pursuit of his duty.

And if he’s Mahler—

Who am I?

Suddenly Mahler saw the insane circle complete. He recalled the jumper, the firm, deep-voiced, unafraid time jumper who had arrived claiming to have a two-way rig and who had marched off to the Moon without arguing. Now Mahler knew who that strange jumper was.

But how did the cycle start? Where had the two-way rig come from in the first place? He had gone to the past to bring it to the present to take it to the past to—

His head swam. There was no way out. He looked at the man behind the desk and began to walk slowly toward him, feeling a wall of circumstance growing up around him, while in frustration he tried impotently to beat his way out.