A genuinely stupid boy stumbles into a war he doesn't understand and solves it by being too kind to let anyone die. The show treats him like an idiot and then proves he's right, that gentleness in a mecha anime is its own superpower. Every character Photon meets wants to use him, and he just keeps writing "baka" on their foreheads until they become his friends instead.

Photon Earth is a gentle young man with superhuman strength and the word "idiot" scrawled across his forehead, most likely the work of his mischievous friend Aun Freya. His life takes a strange turn when he writes the same word on the forehead of Keyne Acqua, a beautiful pilot on the run, and ends up engaged to her. Worse trouble arrives in the form of Papacharino, a villain determined to steal the secrets of "Aho" energy from the ship belonging to Keyne's grandfather. Photon must shield both Aun and Keyne from him. The six-episode OVA mixes action, adventure, comedy, drama and mecha elements, with a dose of ecchi humor.