Perrine Valley is a lieutenant in the 34th Precinct, working alongside officers John Estes and Daizaburo Ban. She tackles complex cases involving organized crime, drug trafficking, and high-risk investigations, leading operations like investigating drug shipments and confronting criminals who hold personal vendettas against her.

She enters a romantic relationship with Daizaburo after he witnesses her competence during confrontations with criminals. Their relationship deepens significantly when Estes arranges their marriage in an effort to revive Daizaburo from a coma after a critical injury. Although this marriage is later annulled, they remarry during a hostage crisis where cowboy assassins abduct the trio.

Her past includes traumatic events: a crime boss she arrested targeted her, orchestrating a gang rape as retaliation. She also endured workplace harassment from corrupt superiors within the police department.

Demonstrating physical prowess in law enforcement operations, Perrine primarily functions as a stabilizing influence within the precinct team. Her character development remains secondary to the central partnership between Estes and Daizaburo.