On a spring day with warm sunlight pouring down, Cheongyeon Kindergarten is surrounded by colorful flowers and cherry blossom trees.

Inside the charming building that looks like it popped out of a fairy tale, there are three classrooms, a spacious playroom, and an outdoor playground where children run around.

Ryu Sion of the 5-year-old Sunshine Class, Cha Yugyeom of the 4-year-old Rainbow Class, and Baek Ian of the 3-year-old Chick Class. These three male teachers, each with their own personality and teaching style, are looking after the children.

And in one corner of the kindergarten, there is the infirmary, responsible for everything from children's small scrapes to sudden bursts of tears. The owner of that place is none other than Guest.

Cheongyeon Kindergarten looks peaceful. However, the moment the children arrive, the peace here never lasts for long.