Alpha Trax train guard Joe Griffin is forced to do a shift on one of the overnight passenger trains, which is scheduled to
depart London at midnight because the regular train guard has taken sick leave. His only consolation is the chance to spend
time with his unrequited love, the tea-trolley girl, Ellen. The full moon pierces through a heavy thunderstorm as the train
travels. A few miles before the final station, Eastborough, the train nearly derails in a forested area when it hits a deer.
When the driver checks the situation, he finds the dead deer stuck to the wheels. While removing the deer, he gets some of its
blood on him which attracts the attention of a werewolf, and is attacked and killed. Unaware of the danger, the remaining
passengers - Kate, Adrian, Matthew, Billy, Nina, Paul, Ged, and his wife Jenny - are angry to learn that an emergency team won't
be able to reach the train due to downed trees all along the line. They cajole Joe and Ellen into letting them off the train to
walk to Eastborough. As they walk through the woods, Joe and Ellen find the driver's eviscerated body. They rush everyone back
to the train, but a werewolf pursues them, biting Jenny on the leg before the rest can pull her to safety. As the others bandage
Jenny's wound, Joe tries to call for help again but receives no response. Soon everyone realizes they have no cellphone
reception. Billy, an engineering student, determines that the fuel lines were damaged and leaking, which will need to be
repaired before the train can move. The werewolf tries to force its way into the cabin but cannot penetrate the metal roof or
double-paned windows. However, when Nina's phone begins to ring, and she moves into a less secure area of the car, the werewolf
smashes through the window and pulls her out. The remaining passengers barricade themselves in another car, using the train's
power tools to reinforce the windows and doors with metal grates. Paul, who is suffering from diarrhea, is killed when the
werewolf manages to enter the car through the bathroom roof. It then breaks through the passengers' barricade, but the passengers
fight together and kill it. Matthew recognizes the creature as a werewolf, and Adrian recalls that someone bitten by a werewolf
will become one. Over Ged and the others' objections, Adrian tries to kill Jenny, who is becoming disoriented, spitting up
blood and her teeth before becoming a werewolf. Joe knocks Adrian unconscious, then has the others tie up him and Jenny.
Unaware that the werewolf's death cries have alerted the rest of its pack, Billy and Joe develop a plan to repair the train and
drive it to safety. As Joe and Ellen monitor the console, Billy goes out to improve the fuel lines. Matthew is to be his guard,
but he disappears into the forest when he hears a voice calling for help. He discovers Nina being eaten alive by a werewolf and
is then attacked and killed himself. As the train begins to move again, the werewolf pack pulls Kate to her death. Jenny
transforms into a werewolf and kills her husband. Before she can kill Adrian, Joe kills her. The other werewolves board the
train, and Adrian traps Joe and Ellen to cover his escape. Billy tries to beat off the werewolves with torches but is killed.
Joe and Ellen flee into the forest, pursued by the werewolves. Realizing they will be destroyed, Joe stays behind to fight them
as Ellen safely makes it to the nearest station. Joe fights bravely, but he is bitten by the chief werewolf. Shortly after that,
Adrian stumbles onto the scene and is attacked by the newly transformed Joe.
