Thorium sits mostly untapped as a nuclear fuel, and this film follows the loose network of engineers, bloggers, and amateur enthusiasts pushing to change that. Produced by Motherboard, it tracks a grassroots case for thorium reactors as a safer, more abundant alternative to uranium, built less inside corporate R&D labs than online, in forums and conference talks where advocates argue the technology was shelved decades ago for reasons that had more to do with weapons programs than physics. The film treats the movement as a test case for how a stalled energy idea might get revived from outside the usual institutions, showing the people making the pitch rather than a finished reactor. It stays close to the advocates' own arguments and enthusiasm, leaving the harder engineering and regulatory questions mostly implied rather than answered on screen.