In class, next to Yokoi is a boy named Seki-kun who is constantly occupied with activities at his desk. He has a knack for playing elaborate games unnoticed by the teacher. With games ranging from dominos to shogi, go, mecha models, and even playing with cats, he always has something new up his sleeve. Yokoi hesitantly gets intrigued by his games, but unfortunately, they tend to land her in trouble with the teacher.