Romantic Killer follows the hilarious misadventures of Anzu Hoshino, a high school student whose perfectly content life revolves around three passions: video games, her beloved cat, and chocolate. Her peaceful existence takes an unexpected turn when a magical fairy named Riri appears with a peculiar mission – to force romance into Anzu’s decidedly unromantic life. This intervention is part of a larger scheme by the magical world to address Japan’s declining birth rate, which has led to a shortage of children’s innocent energy that powers their realm.

What unfolds is a delightful battle of wills as Anzu actively resists every romantic scenario thrown her way, even after Riri confiscates her precious distractions. However, fate (and Riri’s magic) has other plans when Anzu literally crashes into Tsukasa Kazuki, the school’s resident heartthrob whom she had previously paid no attention to. Despite her best efforts to sabotage the magical world’s matchmaking attempts, Anzu finds herself increasingly entangled in situations that push her towards romance, creating a charming story that cleverly subverts typical shoujo manga tropes while exploring themes of personal choice and authenticity in matters of the heart.