Souya Kuroi experiences a far-from-ordinary life. As he envisions battling powerful figures against a massive dragon in the sky, he struggles with amnesia and cohabits with a maid and a cat-like humanoid. However, his reality takes a bizarre twist when a bear-shaped UFO emerges in Sorimasaka City and globally, and seven champions endowed with glimmering rainbow abilities confront it, mirroring his dream. To make matters more peculiar, the maid urges him to forsake his sanctum and challenge these heroes to gain their energy source.