"Y-you _what_?" This time it was McCurdle whose voice cracked on a dismal note. "I was assigned to guard this sector, sir--" "Don't repeat, Pettigrew!" The baffled topkick gave vent to a groan. "I heard you the first time. _You!_ On duty at this post! Of all the muddle-headed assignments--Damn it, man, this Armory is one of the most vital military objectives in the whole city!" "It--it is?" piped Peter with sudden eagerness. "Perhaps _the_ most important! Pettigrew, do you know the entire basement of this building is filled with gunpowder and dynamite? Enough to blow the surrounding neighborhood to Kingdom Come! And within three city blocks of here stand the City Hall, the Federal Building, two factories engaged in war armaments production, and a Marine barracks!" "Th-there are?" gulped Peter with less eagerness. "And of all men," despaired McCurdle, "_you_ had to be assigned to this post. And in less than a minute the warning will be sounded. Well--" He shrugged--"It's too late now. It's your pigeon. You've drawn your equipment?" "Equip--Oh, yes, sir! Right here!" Peter patted a gas mask container at his side and, rather more gingerly, the automatic at his hip. "I'm all-ready, sir." "Very well, Pettigrew. From now on--" The topkick had to raise his voice to a bellow to make himself heard over the banshee blast that had suddenly wakened and howled from a hundred simultaneous sources--"it's up to you! Carry on!" And as the gray gloom of the city night was suddenly engulfed in ebon black, as feverish eyes of electric and neon blinked out one by one over a city grimly readying itself for any eventuality, Sergeant McCurdle moved into the darkness--and was gone! * * * * * At first his disappearance was a relief to the small would-be Air Warden. Then, as the ear-shattering sirens died into muted silence, as McCurdle's footsteps pattered off into murkiness, a vast, enswaddling stillness descended upon Peter Pettigrew--and with it came stark realization of his perfect aloneness. In Stygian gloom he murmured, "Oh, my goodness! I'm all alone!" and raised a trembling hand before his eyes. It was a vague, white blob in the darkness. Tingling fingers of panic clutched at Peter's nerves, and his ganglea hummed like harpstrings. "Oh, my soul!" he jittered. "It's so _dark_!" Civic authorities had deliberately chosen a moonless night for this experiment. Mother Nature had collaborated by veiling the sky with a thick overcast, making the night starless as well. The street upon which Peter stood was as black as a whale's belly. Except for-- "Oh, mercy me!" bleated Peter, "this will never do!" And his panic subsiding in the face of this unallowable thing, he scurried down the street to a dwelling beneath the lowered blinds of which escaped one lone, betraying slant of light. Hastily he ascended its steps, more hastily rapped on the door. "Lights out!" he cried. "Air alert! Lights--"