"When a Watcher learns a physicist is close to the one key to success in his effort to make a hydrogen bomb--an equation that begins: 'Twelve times zero point seven nine'--we are notified and a killer from our own people is sent to execute that scientist. Yes, Martin Kirk, we have those among us--a very few--who are capable of killing on orders and for cause. Naia, here, is one of them. She was sent to take the lives of Gregory Gilmore and Juanita Cordell; but she bungled and instead of their deaths resembling heart failure, they were obviously murdered. "Alma Dakin tried to cover up the truth by making it appear both scientists had died at the hands of a jealous husband. She succeeded, both because of her perjured testimony and the fact that Paul Cordell insisted on telling the truth. But when we of Mythox learned what had happened, Naia was sent back to confess the crime. She entered the laboratory only a few hours before she came to your office; while she was in the laboratory the second time, the clues you found were put there. "Our mistake was in thinking that, once proof was offered clearing Cordell, the innocent man would be freed. For once more we credited Earthlings with the same code of ethics we of Mythox adhere to. "You succeeded in following Naia here. Only a man composed of equal parts of Earth bulldog and genius could have done so. Martin Kirk, I offer you a place among us and a lifetime devoted to making sure the galaxy of which we both are a part does not perish. What say you?" Several minutes dragged by. The eyes of both Tamu and Naia North were glued to the grim visage of Homicide Lieutenant Kirk. It was impossible for either of them to know what thoughts were churning behind that stone face. Abruptly he stood up. "I'm a cop. I leave your kind of problem to the people who are good at it. My people, Tamu. You see, I belong to my world, not to yours. "But you've got a solid argument--one I'd be a fool not to consider. Let me sleep on it. Tomorrow morning we'll talk about it some more; then I'll give you my answer. Right now I'm too worn out to think in a straight line." "Of course." The overlord rose to his feet. "Find Martin Kirk comfortable quarters, Naia, and leave orders he is not to be disturbed until he is ready to join us." On his way down a corridor behind the same slip of a girl who had brought him his drink, Martin Kirk was thinking: They didn't even frisk me for a gun! Martin Kirk went into his apartment and lay for a while looking at the ceiling. After a time, he got up and went out again. Chapter IX