Kazuya Nambu, a chubby and dull high school student who escaped into a locker after being accused of peeping, was transported to another world as a hero. The guide – fairy Elle, said that Kazuya was given the ability to instantly recover even from minor damage -『Super Regeneration』, but his physical ability was still poor…!? Kazuya, with physique, gradually raised his level by defeating small fries. And when Kazuya’s hidden skill『Protect』was activated, Eva, Fine, and Alicia began to fall in love…!?