Anime List

Kumiko "Yankumi" Yamaguchi enters Shirokin Gakuen Private School to become a math teacher. She's assigned as the homeroom teacher for class 2-4, populated by a gang of delinquents. At first, the class tries everything to rattle her cage, but to no avail. In a short period of time, Yankumi gains the respect of the class. But what the school doesn't know is that she's the heir to the Oedo Group, a powerful Yakuza clan. So while Yankumi struggles to excel in her career as a teacher, she must also keep her Yakuza background a secret.

Mafia is rife in America where assassinations are a regular occurrence on the streets. Inferno, a mysterious company, is behind most of these dealings through the use of their near-invincible human weapon, "Phantom." One day, a Japanese tourist accidentally witnesses Phantom’s latest murder. Desperate to escape, the tourist hides in a secluded building. However, Phantom, revealed to be a young woman named Ein, and the leader of Inferno ‘Scythe Master’ captures the tourist and brainwashes him.