Back Street Girls

A group of 3 yakuza failed their boss for the last time. After messing up an important job, the boss gives them 2 choices: Honorably committing suicide, or go to Thailand to get a sex reassignment surgery in order to become "female" idols. After a gruesome year long training to become idols, they successfully debut, with overwhelming popularity, much to their dismay. This is where their tragedy truly begins.

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AnimeNewsNetwork (anime)