"Working," Rick said. "We scientists must never rest. We must labor always to push back the frontiers of ignorance." He put a hand on his heart and bowed with proper dramatic modesty. "I am working on an invention that will startle the civilized world." "We will now bow our heads in reverent silence while the master tells all," Scotty intoned. "I know," Jerry guessed. "You're working on a radar-controlled lawn mower so you can cut the grass while you sit on the porch." "That's too trivial for a junior genius like Rick," Scotty objected. "He's probably working on a self-energizing hot dog that lathers itself with mustard, climbs into a bun, and then holds a napkin under your chin while you eat it." "Not a bad idea," Rick said soberly. "But that isn't it." "Of course not," Hartson Brant put in. "You see, I happen to know what it is, due to a little invention of my own--an electronic mind reader." Scotty gulped. "You didn't tell Mom what happened to those two pieces of butterscotch pie, did you? I wanted her to blame it on Rick." Rick asked unbelievingly, "An electronic mind reader? All right, Dad, what am I working on?" "A device to penetrate the darkness." Rick stared. His father had scored a hit. He demanded, "How did you know?" "My new invention," Hartson Brant said seriously. "Oh, and one other clue. Yesterday morning the mail brought me a bill for a thousand feet of 16-millimeter infrared motion-picture film." So that was it. Rick grinned. "I hope your new invention told you I asked the film company to send the bill to me and not to you." "It did. The bill actually was addressed to the Spindrift Foundation, attention Mr. Brant. Since I didn't know which Mr. Brant was meant, I opened it. Don't worry, Rick. I'll let you pay it." "Thanks, Dad," Rick said. "But don't make any sacrifices. You can pay it if you want to." "Don't want to," Hartson Brant replied. "I haven't the slightest use for motion-picture film." "Because Rick has the only motion-picture camera on the island," Scotty finished. He frowned at his friend. "Keeping secrets, huh?" "I'm not sure it will work," Rick explained. He hated to brag about an idea and then have it turn out to be a dud. Consequently, he seldom mentioned that he was working on anything until he knew it would be successful. "What does the film have to do with penetrating the darkness?" Jerry Webster inquired. Rick caught the look of interest on his father's face. "Ask Dad," he said. "The electronic mind reader probably has told him all about it." "Of course." The scientist chuckled. "Rick is planning to take movies at night without lights." Jerry looked skeptical. "How?" Rick stood up. "Long as we've started talking about it, I may as well show you." The others rose, too. As they did so, a shaggy little dog crawled from under Rick's chair where he had been napping. "Dismal and I will put the cake away," Mrs. Brant said.