Nobuhiko Ōbayashi attends night classes at Matsutani Junior High School with Chocola. He presides over the school's Science Fiction Club and ardently believes in extraterrestrial life, UFOs, and futuristic possibilities. However, he firmly rejects the existence of traditional supernatural entities like vampires and werewolves, viewing them as myth. This skepticism causes recurring friction with Chocola, a fellow SF club member who joins partly to be near him. Despite her efforts, he remains unconvinced of her true nature.

Later, Nobuhiko transfers to a day school following his father's job relocation. He continues visiting Matsutani Junior High, maintaining contact with Chocola and the SF club. His activities include spending time with Chocola, such as walking on the beach where they encounter other mysterious creatures and situations. Nobuhiko's role centers on his school interactions and relationship with Chocola, defined by his contrasting beliefs in the scientific versus the paranormal.