The series follows a girl named Yokoi Rumi who is constantly distracted by her neighboring classmate, Seki Toshinari, as he indulges in elaborate hobbies and somehow never gets caught in the process.
Rumi is the main protagonist and narrator of Seki's games. She continuously attempts to pay attention in class but is almost always distracted by her neighour's antics. She sometimes tries to make Seki concentrate in class by sabotaging his projects, but usually finds herself joining in on them, though Seki misunderstands these attempts. She has a bob-cut white hair that gradiants down to pink, brown eyes, and is rumored to like Seki.
Normally referred to by his surname, Seki is Rumi's classmate and is the cheerful and mysterious titular character. He is always playing games at his desk, from intermediate to incredibly complex, though he never seems to study. In his desk is a complex array of well-organised objects arranged in a way that if disturbed by anyone but himself, it will be impossible to put back together. He almost never speaks. He has short black hair, green eyes, and is somewhat enigmatic.
"Meiwaku Spectacle" by Hanazawa Kana
"Set Them Free" by Jimbo Akira
Hanazawa Kana as Yokoi Rumi; Shimono Hiro as Seki Toshinari