Deep in the forest, far from any human contact, there lives a child named Ryouma Takebayashi. He engages in the rather strange hobby of keeping various types of slimes as pets. Furthermore, despite his young age, he has a sturdy physique and good compatibility for magic. All of this is because, having endured much hardship in his previous life, three gods grace Ryouma with a second chance to pursue one goal: savor the wonders of life.

After three years of comfortable solitude pass by, Ryouma meets people that will change his current life forever. When he encounters and helps some soldiers tend to their wounded comrade, the group convinces him to accompany them to visit the nearby town's ducal family. Ryouma agrees and soon embarks on a journey to explore the vast world beyond his home.