When Mashiro brings home a failing test grade and decides to run away from home, she wishes for the impossible: a way to erase the bad grade from her parents memories entirely. As she indulges this fantasy, a strange girl wearing an eyepatch and a neon pink hoodie suddenly appears, dragging a suitcase behind her. This mysterious figure vanishes as quickly as she arrived, leaving behind only a small box and a black book filled with bizarre products for sale. The catalog contains items like an Instant Grim Reaper, a Friend Raffle, an Execution Kit, and most temptingly for Mashiro, a Memory Erase Button. The story follows Mashiro as she must decide whether to dare using these freaky items and discover what consequences they might bring. The series is set in contemporary Japan, following not only Mashiros initial encounter but also a collection of short stories about various customers who purchase products from the eyepatch girl and her shadowy partner, leading to unexpected and frightful outcomes. As the narrative progresses into later volumes, readers learn that this mysterious duo is deliberately collecting despair from their customers, raising the question of what their true agenda might be and what they have in store for those who dare to place an order from the Catalog of Wonders.