A prequel to Himitsu that follows Maki Tsuyoshi and his best friend Suzuki Katsushiro during their college days. o412

The year is 2045, when MRI technology was still in its nascent stages. A decade ago Maki's parents were killed in a fire, and since then he's been living with his legal guardian Sawamura Satoshi, who suffered severe burns while rescuing him. Though he's convinced that his parents were murdered, Maki has no clues to help him find the culprits other than the hazy memory of a certain symbol.

Upon discovering that this symbol is associated with a powerful secret society called that's based in Tokyo University, Maki enters the same college, hoping his top credentials will get him an invitation to . He isn't chosen, but the more socially adept Suzuki is. Maki approaches Suzuki in hopes that he'll lend him his aid, and the two embark on a hunt for the truth.