King Marker

Rei, a high school student, receives a strange email on her new cell phone containing an infinite symbol. When she opens it, a young boy named Rouel magically appears before her. He claims to be a king and declares that Rei must grade his performance as a ruler. Now, Rei and her younger brother Ichita must take care of Rouel in their home.

As Rei begins to evaluate Rouel's actions, she discovers that his presence brings both wonder and chaos into their ordinary lives. The young king's unfamiliarity with the human world leads to a series of unexpected events, forcing Rei to balance her daily responsibilities with her new role as a judge of royal conduct.