“There’s not much to tell,” said Hartnett slowly, after the meal had been finished. “We started out in the Orion much the same as you did in the _Columbia_, tested the contracels and decided everything was all right. We noticed this little world here and landed to investigate. “Only we couldn’t get off. “We’d been going virtually at the speed of light and that warped the fourth dimensional fields which were a basic part of the contracels. We found that the only way we had of getting off this planetoid was by rockets, and rockets weren’t enough. We just slid along the surface, battered up the ship, then stopped. “Then we began to find out things about this world. Some of them were interesting, and some—” he broke off suddenly. “Nick, you or none of your party have been out without full suits have you?” Nick shook his head. “Good. Don’t. This little world is full of radiations, a good deal of which are undetectable, but nasty nonetheless. Seven of our party succumbed before we suspected anything was wrong, and five more died within the next fortnight from perfectly innocent things which must have acted as catalysts. “So far as we know, an ordinary suit is protection, but we can’t be sure.” “What happened to the others?” asked Bob Vickers. Hartnett was silent for a moment. “When we landed, one of the rocket fuel tanks was ruptured. Not broken open, just cracked enough to let the stuff vaporize and escape. It started to flood the ship gradually, before we found out. We drew lots to see who would seal off the rooms where it had already penetrated, knowing that the chances were a hundred to one that everyone who went would be blown up. It was a suicide job, but those suicides could keep the entire ship from being blasted to free electrons. “They did. If you’d come from the other side, you’d have seen the great gaping crater and the hole in the ship.” “I don’t understand....” started Dorothy. “I do,” spoke up Nick. “When the Orion left, the only rocket fuel which was any good was HZ 7. It had one fault, however. Let any atmosphere get at it and it would vaporize and seep through practically every known substance, except wax. And that vapor was about ten times as touchy as nitro. When it went off you had a terrific explosion. “What these fellows did, I take it, Steve, was to seal off the sections from the outside, leaving plenty of room for the vapor to explode, perhaps calculating on its drawing closer while they were at work. Then, they went to work on padding so that the concussion wouldn’t completely wreck the ship. Their only chance of escape was completing the job and getting off before the stuff lit up. And working around it was almost a positive guarantee of setting it off.”