Time travel has drawn serious physicists and outright cranks into the same conversation ever since Einstein's equations left the door open for it, and this film walks through both camps without much distinction between them. Aage Nost demonstrates a homemade time machine on camera, a mathematician appears hooded in a ski mask to explain his theories, and someone proposes mailing a pizza backward through time as a thought experiment. Professor Frank Tipler of Tulane University gets more serious treatment: his design for a working time machine is physically sound on paper but would require a mass roughly half that of the galaxy to build. Later sections turn to the idea that a sufficiently advanced future civilization could run computer simulations detailed enough to recreate the past exactly, which several physicists interviewed find less like innovation than an ethical problem. The film does not resolve whether any of this is achievable. It ends instead on the unsettling possibility that a simulated past would be indistinguishable from the real one.