Tenjin, a 27-year-old educator, leads the series. His focus is on training students for high school and middle school entrance exams at a cram school. Tenjin is skilled in teaching younger students despite his lack of affection for children. He carries out his lessons with detachment but supports his colleague, JD, while also facing life's obstacles. A fifth-grader unexpectedly confesses her love for Tenjin, witnessed by 14-year-old Seika, during a session. Seika manipulates the situation by forcing Tenjin to provide her with "private lessons" at night.
