"Xpress Train" is a science fiction anime series set in a dystopian future where humanity relies on a massive, high-speed train network to traverse a desolate, uninhabitable world. The train, known as the Xpress, is a self-sustaining ecosystem carrying the remnants of human civilization. Divided into rigid class systems, the train's passengers are segregated by wealth and status, with the elite residing in the luxurious front cars and the impoverished struggling to survive in the overcrowded tail sections.

The narrative centers on a young protagonist, Kaito, a resourceful and determined individual from the tail section who becomes embroiled in a rebellion against the oppressive regime governing the train. After discovering a hidden message from the train's enigmatic creator, Kaito learns of a secret plan to reset the train's course and restore balance to the fractured society. This revelation sparks a journey that forces Kaito to navigate the train's treacherous hierarchy, forming alliances with passengers from different classes, including a disillusioned engineer, a former elite enforcer, and a mysterious stowaway with ties to the train's origins.

As the rebellion gains momentum, tensions escalate between the tail and front sections, leading to violent confrontations and moral dilemmas. The series explores themes of class struggle, survival, and the ethical implications of technological control. Kaito's leadership is tested as he grapples with the consequences of his actions and the sacrifices required to achieve a just society. The train itself serves as both a setting and a symbol, representing humanity's dependence on technology and the fragility of social order.

The plot unfolds through a series of escalating conflicts, with each car of the train presenting unique challenges and revelations. Key characters include Kaito, whose idealism drives the rebellion; Aiko, the engineer with insider knowledge of the train's systems; Ryota, the conflicted enforcer torn between duty and morality; and Hana, the stowaway whose past holds critical clues to the train's true purpose. The series balances action, intrigue, and character development, culminating in a climactic struggle for control of the Xpress and the future of its passengers.