High school student Hayato Katsuragi dies in a traffic accident and is reincarnated as Reivelt Runwalker, the son of a noble in another world.

At the time of his reincarnation, the goddess bestows upon him a cheat skill with no level limit, but at the same time, he also acquires the most terrifying skill, “The One Afflicted by Hardship”.

With his life now guaranteed to be in hard mode, Reivelt resolves to undergo training and become stronger.

While receiving his lessons, he enjoys a happy life alongside his cute maid and his little sister, but then they are attacked by a massive horde of monsters all of a sudden!