"I know, lad. I've seen the way you looked at her. But remember--forty thousand innocent lives! Had she learned the secret of that new weapon, our voyage might have been disastrous. From this distance she could have made a flight to Io in one of the auxiliary safety rockets, given the plans to Kreuther's forces. The very weapon we look to for salvation would have been used against us. Io might have become a nest of rebellion, instead of a peaceful member of the solar family. Now that we've snared our spy, the messenger--whoever he is--will be safe." On the visiplate it was a glowing red spark, but in the _perilens_ before him it was a gigantic orb dominating the heavens through which the _Libra_ hurtled. Jupiter; monster of Sol's scattered brood, untamed sphere of writhing gases and vague mystery, itself a pseudo-parent emanating enough heat to make its far-flung satellites livable worlds. Soon they would fling themselves, they aboard the _Libra_, halfway around that gigantic orb, settle to the small body now wanly visible as a silver crescent. * * * * * Dan Mallory punched a control-key savagely, felt the _Libra_ shake itself into a slightly changed curve, turned to his superior. "I'm not so sure of that, sir. Oh, I'm not trying to defend Lady Alice. Earth's Intelligence officers don't make mistakes--not mistakes of that magnitude, anyway. But there are other passengers I don't trust. Lemming. Wilmot. Dr. Bonetti. Why are they aboard the _Libra_? Why were they so excited when they heard we'd received a message from Lunar III? Suppose one of them is also a spy?" "Or suppose," said the skipper, "one of them bears the secret of the new ray weapon. Wouldn't that one naturally be excited?" "But the others?" Mallory inquired. "I don't know. You may have something there, Daniel. I'm still taking no chances. I've put Aiken on guard at Lady Alice's door. If anyone tries to liberate her--What _is_ it, Sparks?" He snapped the query at the intercommunications box which was spluttering and growling. The radioman's tone was weary. "It's Mr. Wilmot again, sir. He insists on talking to you." "Tell Mr. Wilmot I will see him at midday mess." Sparks was stubborn about it. "But he insists his message is important, sir. He demands to see you at once. Says--" "_Demands!_" The skipper's jowls reddened. "Please tell Mr. Wilmot passengers do not _demand_ favors of spaceship officers. I will see him at mess. That is all!" And he cut the communications board; turned to Mallory angrily. "That's why I didn't put you on report for slugging Norton. Wilmot's mad as a hornet and I don't blame him. Norton catting around after his wife--" Chandler appeared, grinning. He said to Mallory, "What a sock, pal, what a sock! If that guy counts sheep in his sleep, he's going to wake up allergic to mutton. Wish I had done it. He's a grouchy son-of-a-- What's biting you?"