The story of Rewrite:SIDE-B is set in the fictional city of Kazamatsuri, a modern Japanese metropolis where decades of aggressive tree planting and afforestation have transformed the urban landscape into a dense, almost jungle-like environment choked with vegetation. The protagonist, Kotarou Tennouji, is a sharp-tongued and somewhat self-absorbed high school boy who possesses a unique superhuman ability: he can permanently rewrite any part of his own body, temporarily enhancing his strength, speed, or other physical attributes. Despite this power, Kotarou leads a largely frivolous life, pestering his delinquent friend Haruhiko and nursing a crush on the oddball childhood friend Kotori Kanbe. His ordinary routine is shattered when he encounters Akane Senri, the sole member and president of the school's nearly defunct Occult Research Club, a mysterious girl others call the Witch. Intrigued by her and by the promise of the supernatural, Kotarou agrees to revive the club. He recruits Kotori and then three other girls: the clumsy transfer student Chihaya Ootori, the strict and sharp-tongued class representative Lucia Konohana, and the quiet, unassuming Shizuru Nakatsu. As the newly formed Occult Club engages in a series of shared adventures investigating local paranormal rumors, Kotarou begins to unravel hidden secrets tied to each member. These encounters inevitably draw him toward a strange, alternate dimension of Kazamatsuri, a silent, gray-skied world that seems to exist alongside the real one. This manga primarily adapts the Shizuru Route from the original visual novel, focusing on Kotarou's deepening connection with Shizuru as the stakes escalate. It is one of two complementary manga adaptations; Rewrite:SIDE-B follows the path Kotarou takes when he chooses to focus on himself and his personal bonds, while Rewrite:SIDE-R follows the path where he chooses to confront the wider world. Through this journey, Kotarou is forced to face a fate that only he may have the power to rewrite.