On the quiet, cratered surface of Jupiter's largest moon, twelve-year-old Leo’s pockets don't jingle with coins—they jingle with the bright, metallic chatter of sprockets, cogs, and widgets. As the resident Gadgeteer of Ganymede, his workshop is a haven of humming machines and half-finished inventions, with his loyal robotic sidekick, Astro-Pup, always at his feet.

But when a sudden and unsettling silence falls over the entire colony, cutting off all communication with the outside solar system, Leo's talent for tinkering becomes their only hope. Armed with a set of forgotten blueprints from his legendary inventor grandmother, he must build a device of breathtaking complexity: the Star-Catcher 9000.

To find the parts, Leo must embark on a thrilling journey across the moon's treacherous Shadow Side, bargain with grizzled prospectors in the Asteroid Belt scrapyard, and face strange, crystalline creatures in deep, forgotten caverns. Along with a new friend from the icy colony of Europa, Leo races against time to assemble his masterpiece, all while evading the schemes of a jealous administrator who wants the Star-Catcher for his own greedy purposes. It's a story of ingenuity, friendship, and courage, where one boy's pocketful of spare parts might just be enough to relight the stars and save his world from an endless silence.