After a string of mysterious disappearances begin to plague a train, the Demon Slayer Corps' multiple attempts to remedy the problem prove fruitless. To prevent further casualties, the flame pillar, Kyoujurou Rengoku, takes it upon himself to eliminate the threat. Accompanying him are some of the Corps' most promising new blood: Tanjirou Kamado, Zenitsu Agatsuma, and Inosuke Hashibira, who all hope to witness the fiery feats of this model demon slayer firsthand. Unbeknownst to them, the demonic forces responsible for the disappearances have already put their sinister plan in motion. Under this demonic presence, the group must muster every ounce of their willpower and draw their swords to save all two hundred passengers onboard. Kimetsu no Yaiba Movie: Mugen Ressha-hen delves into the deepest corners of Tanjirou's mind, putting his resolve and commitment to duty to the test.

Ever since the death of his father, the burden of supporting the family has fallen upon Tanjirou Kamado's shoulders. Though living impoverished on a remote mountain, the Kamado family are able to enjoy a relatively peaceful and happy life. One day, Tanjirou decides to go down to the local village to make a little money selling charcoal. On his way back, night falls, forcing Tanjirou to take shelter in the house of a strange man, who warns him of the existence of flesh-eating demons that lurk in the woods at night. When he finally arrives back home the next day, he is met with a horrifying sight—his whole family has been slaughtered. Worse still, the sole survivor is his sister Nezuko, who has been turned into a bloodthirsty demon. Consumed by rage and hatred, Tanjirou swears to avenge his family and stay by his only remaining sibling. Alongside the mysterious group calling themselves the Demon Slayer Corps, Tanjirou will do whatever it takes to slay the demons and protect the remnants of his beloved sister's humanity. [Written by MAL Rewrite]

Chuuta Kokonose is an orphan who lives with his aunt. For as long as he can remember, he's had a voice in his head, but other than that he's a normal boy—right until the day when a strange-looking thing follows him home and teleports him to a place filled with more fantastic creatures. It's a space police station, and Rein Brickke, the Chief of Solar System Department, tells him that he's been chosen by the computer as a possible candidate to join the police force. Misuzu Sonokata, a girl from Chuuta's school with an angelic face and ill temper who turns out to be one of Rein Brickke's subordinates, doesn't think him suitable for such a job. Chuuta, who was shocked at first, decides to take the aptitude test after being urged by the voice in his head and to prove Misuzu wrong.

TV version of including an entirely new first episode. The first episode depicts Rengoku as he embarks on his journey to the Mugen Train. The remaining episodes will add about 70 new animation cuts and new background music, as well as a new trailer. (Source: ANN)