"Chikan Jūnin-tai The Animation" is an adult anime series that centers around a group of individuals who engage in inappropriate behavior on public transportation. The narrative unfolds in an urban setting, where the protagonists, a group of ten men, form a clandestine organization dedicated to harassing women on trains. Each member of the group has a distinct personality and approach to their actions, which are depicted through various scenarios across the episodes.

The series is structured around episodic encounters, with each episode focusing on different victims and the methods employed by the group. The interactions are characterized by a lack of consent and are portrayed in a manner that emphasizes the predatory nature of the group's activities. The victims, primarily women, are shown in vulnerable situations, often unable to escape or seek help due to the crowded and confined environment of the trains.

The main characters include the leader of the group, who orchestrates the activities and ensures the group's cohesion, and several other members who each bring their own tactics and motivations to the table. The series does not delve deeply into the backgrounds or personal lives of the characters, instead focusing on their actions and the immediate consequences within the context of the train environment.

The plot progresses through a series of escalating encounters, with the group becoming more brazen in their actions as they face minimal resistance. The narrative does not provide a resolution or moral conclusion, instead presenting the events in a straightforward manner that highlights the disturbing nature of the group's behavior. The series is intended for a mature audience due to its explicit content and themes.