Tsukasa Kazami is a young man living in 2020. He sits under a cherry tree and wakes up in 1920 Tokyo — the Imperial Capital of the Taisho era, a city full of ambition and cultural bloom. He falls in with a mysterious British woman who runs a detective agency in the capital alone, under considerable financial strain, and through their association finds himself caught up in a series of incidents neither of them fully understands. The mystery unfolds between the cherry blossoms and the era's romantic optimism, with the question of which period — Reiwa or Taisho — is where Tsukasa's potential truly belongs.