The story is set in a privately owned board game café called Kurumaza, located in the Ogikubo district of Tokyo. Kotaro Tokiwa, a high school dropout who works there as the interim manager, is a dedicated board game enthusiast who has secretly fallen in love with his coworker, Mifuru Takanashi, a high school gyaru who seems to have no interest in board games at all. Kotaro keeps his feelings to himself because Mifuru already has a boyfriend, a charismatic and handsome young man named Itsuki Usa, and the couple often flaunts their relationship in front of him.

To hide his true feelings and deflect Mifuru's persistent questions about his love life, Kotaro claims that he is actually in love with Tsukino Utakata, a well-known local female shogi player. This lie soon spirals out of control, because Tsukino—without revealing her identity—has been a regular customer at Kurumaza under the alias Utamaru. Unknown to Kotaro, the boyfriend she boasts about, Itsuki Usa, is actually a fabricated identity that Tsukino herself created. The central characters are thus entangled in a web of secrets and misunderstandings, where each person's true feelings are obscured by the lies they tell.

As the story progresses, other figures from Kotaro's past emerge. His former best friend before he dropped out of high school, Moena Bugei, reappears in his life, and a girl named Akari Hankui, who claims to be Moena's ex-girlfriend, also makes contact. These reunions force Kotaro and those around him to confront their pasts and their real emotions. The narrative unfolds in a non-linear fashion, with the timeline shifting as layers of misdirection and secrets are gradually peeled away. The series weaves together romantic comedy with mystery-like elements, as every character plays a game of love in which the rules are never fully known.