Tino, Red's brother, can't sleep for fear skeletons will kill him in his dream. Prof uses a machine to visualize his dreams. The Challengers learn everyone in the city (Boulder, Colorado) is haunted. People struggle to stay awake while Prof tinkers the dream machine. He sends Ace, Red, and Rocky into Tino's dream. In eerie black-and-white dream streets, they pursue the skeletons to the docks, then underwater - where lurks a giant tentacled alien-amoeba that's infecting everyones' dreams. The Challengers lure torpedos to kill the monster - and everyone can get some sleep.; Investigating an anonymous tip in Endless Caverns, Ace is coldcocked and fitted with a Man in the Iron Mask mask - that's also a ticking bomb! The Challengers vote to rush Ace to their doctor, Doctor Stevens, even though the bomb endangers the city. The doctor learns the bomb is activated by Ace's heartbeat. The Challengers pack Ace in ice, inducing a near-death state, and the ticking stops. They remove the bomb and return to the Caverns. There the unnamed cadaverous inventor shoots at them. Ace lobs the mask, which starts ticking, and blows its inventor to oblivion.