Mamoru Kagemori is a dull high school boy who's not handsome, athletic, or intelligent. But he is actually the eldest son of the 400-year-old Ninja clan specializing in protecting their neighbors, the Konnyakus! One day a transfer student confesses her love to Mamoru. What will he do? Meanwhile Yuna is abducted by aliens! The world goes crazy as hysterical news of a UFO spreads.