As a corporate slave, Ryouta Satou experiences the worst forms of stress, overwork, and loneliness. Even after he is hospitalized due to exhaustion, his days of toil only become worse. Soon enough, the sheer fatigue catches up to him and kills him in his sleep. However, Ryouta is given a second chance at life: he wakes up in another world as a slime drop—much to the surprise of Emily Brown, the petite blonde girl who defeated said slime. Acquainting himself with the rules of this RPG-like world, Ryouta finds out that he will never grow past level 1. However, he also discovers that one of his skills is at the maximum level: the skill which determines the rarity of monster drops. This allows him to acquire not only items of the best quality, but also some that are unheard of. Ryouta sets out to make the most of his ability—meeting new friends, grinding through dungeons, and acquiring unique items along the way. Reveling in his new life seems to be the long-awaited and much-deserved reward for all the tribulations he had suffered.

Following a bad experience teaching at a public high school that resulted in a break from working, Haruaki Abe eagerly takes up a new job at Hyakki Academy. Despite his cowardice, the novice teacher is motivated to do better this time around. However, his mind quickly changes when he finds out that everyone at the school is actually a supernatural being known as a youkai, leaving him glaringly out of place as the only human around. Facing his class as its new homeroom teacher, Abe immediately becomes a target for the students' antics due to his quick-to-scare nature. Though as the man starts to learn more about the creatures, as well as himself, getting along with the unruly group might not be as hard as he originally thought as their school lives begin to get more vibrant.