Because Rein was a weak and simple beast tamer, he was expelled from the hero's group but that didn't stop his desire to be an adventurer. By taking simple quests afterwards he has a destined encounter with a strong cat girl.
The wizard Haru spent his days being abused by the hero, his childhood friend Leticia, when one day while being scolded he thought to himself, "This is no good". And thus began Haru's adventure to regain his true self! The curtain unveils on an other world "redo" fantasy life!