Mulder finds himself trapped in a bomb-rigged train car with an assassin who he believes was sent to kill the apparent alien currently locked in another part of the train.

Scully, on her own, discovers a leper colony where she learns about some terrible experiments that were conducted by Dr. Shiro Zama who is now dead thanks to the assassin who is on board the train. Scully calls Mulder on her mobile to tell him that there is no such thing as alien abduction after receiving information from one of the Elders working with the Cigarette-Smoking Man. Mulder believes that the 'thing' in the train is in fact an alien and not a leper as Scully suggested. The assassin with him tells Mulder though that the test subject was to be used as a soldier immune to biological warfare. But as the clock on the bomb ticks down, will Mulder be saved or left to die with the thought that everything he's believed about aliens is actually not true..