Hesterson clicked his tongue--or at least the tongue he was wearing. "Oh, dear, that _was_ an error. We tried particularly not to include on our lists subscribers to any of your speculative periodicals. That wasn't my mistake, thank goodness; it was another scout who had the horrible job of spending several days here and compiling the lists. Under your present low radioactivity it's real agony for us." "I'll tell you one mistake you did make, though," said Sam angrily. "You ought to've arranged with the elevator man before your first lot of answers was due. If you want to know, that's how I got onto the whole thing. I'm a mail carrier--I'm retired now, but I was then--and I was the one supposed to deliver the first batch. Mallory--that's the elevator operator--laughed in my face and told me there wasn't any 746 in this building, and I had to take the letters back to the post office--on my _last_ delivery!" Sam couldn't keep the bitterness out of his voice. "After 35 years--well, that's neither here nor there. But I didn't like that and I made up my mind to find out what was happening." "So that's it. Oh, dear, dear. I'll have to compensate for that or I _will_ be in trouble." Sam had had enough. "You are in trouble right now," he growled, pushing the little alien back against the parapet. "We're staying right here till morning, and then I'm going to call for help and take you and your flying saucer or whatever it is straight to the F.B.I." The counterfeit Mr. Hesterson laughed. "Oh, no indeed you aren't," he said mildly. "I can slip right back into my own shape whenever I want to--the only reason I haven't done it yet is that then I wouldn't have the equipment to talk to you--and I assure you that you couldn't hold me then. On the contrary. As you just pointed out to me, I did make one bad error, and my boss doesn't like errors. I have no intention of making another one by leaving you here to spread the news." "What do you mean?" Sam Wilson cried. For the first time, after the years of accustomedness to the idea of extraterrestrial beings, a thrill of pure terror shot through him. "This," said the outsider softly. * * * * * Before Sam could take another breath, the wrist he was holding slid from his grasp, all of Mr. Hesterson slithered into something utterly beyond imagining, and Sam found himself enveloped in invisible chains against which he was unable to make the slightest struggle. He felt himself being lifted and thrown into the cockpit. Something landed on top of him--undoubtedly the package of prize entries and dollar bills. His last conscious thought was a despairing one of Mollie. Sam Wilson, devoted mail carrier, was making a longer trip than any Persian courier ever dreamed of, and not snow, nor rain, nor heat, nor gloom of night could stay him from his appointed round.