Magic and Mystery is a Magic and Mystery crossover fanfic where a young Osamu Dazai is sent to Hogwarts School of Witchcraft and Wizardry while still connected to the Port Mafia and under Ougai Mori’s influence. While acting playful and causing chaos around school, Dazai secretly carries out missions and investigates strange mysteries hidden within Hogwarts. As the story continues, friendships begin forming with students like Blaise, Draco, Hermione, and Ron, while professors such as Severus Snape become increasingly suspicious and concerned about him. The story mixes mystery, magic, humor, and emotional moments as Dazai hides his struggles behind smiles while uncovering secrets around the castle.