Kosaka is an ordinary junior high school girl leading an unremarkable life until she witnesses her classmate Tomine being bullied by other students. After the incident, a strange, oddly shaped creature emerges from Tomine, leaving Kosaka shocked and confused. When she asks Tomine about the creature, Tomine gives only a cryptic response and warns Kosaka to stay away. Despite the warning, Kosaka chooses to involve herself and tries to help Tomine, drawing her into a bizarre and dangerous situation. The creature, referred to as the Great King, is somehow linked to an apocalyptic event that was triggered in July 1999. As Kosaka gets closer to Tomine, she learns more about the mysterious entity and its connection to the end of the world. The story unfolds in a school setting, blending everyday school life with supernatural horror and the looming threat of global destruction. The manga is rendered in striking blue ink, and in addition to the main narrative, the volume includes a second story about an unusual romance between a girl and a bug.