The agents are called to a hotel in Richmond, Virginia by Detective Kelly Ryan, one of Scully's ex-pupils at the academy. Ryan, who is working her first case, is stymied by the disappearance of several people. The latest victim, Patrick Newirth, vanished from his hotel room. The only clue to his whereabouts is a mysterious scorched pattern burned into the carpet beneath the door to his room. Mulder notices that a light bulb in the room had been unscrewed from its socket. He had it dusted for finger prints.
     The agents travel to the residence of another victim. There they discover another loose light bulb and a scorch mark. Among the items found in the victim's trash is a train ticket. The agents realize that all three victims traveled through the Richmond train station before they died. Policemen are dispatched to stake out the station. They attempt to stop a man, Chester Ray Banton, for questioning, but Banton runs away from them. Cornered in two bright pools of light, Banton warns the officers to stay back. When the officers step on his shadows, they vaporize in a fiery burst of light.
     Mulder and Scully review video footage recorded by the train station's security system. They discover that Banton sat around the station for days staring at the ground. An insignia on his clothing leads them to a company called Polarity Magnetics, where aDr. Davey gives the agents a tour of the facility. Davey explains how Banton, who is a scientist, performed research on dark matter such as quantum particles, quarks and neutrinos. One day, according to Davey, Banton became trapped inside a particle accelerator room and was exposed to a massive amount of energy-which literally burned his shadow right into a wall.
     Mulder reviews the videotaped security footage and realizes Banton was sitting in an area where florescent lighting did not cast any shadows. Shortly thereafter, the agents corner Banton at the station. Again, he warns them to stay back. As his shadow creeps towards Scully, Mulder raises his gun and shoots an overhead light bulb, plunging the area into darkness. Banton is relieved.
     Banton is transported to a psychiatric hospital and imprisoned in a room with soft light. During an interview, Banton insists to Mulder that the government is hunting him down in an effort to learn his secrets. Detective Ryan then informs the agents that their services on the case are no longer required.
     Frustrated, Mulder seeks out X, his shadowy government contact. But X insists he cannot be of any help to him. A short time thereafter, X and some paramedics attempt to kidnap Banton from the psychiatric facility. The paramedics come in contact with Banton's shadow and are vaporized. The scientist emerges from his room and escapes.
     Banton returns to Polarity Magnetics intent on destroying himself inside the particle accelerator. Detective Ryan arrives at the scene and attempts to arrest Banton, but she comes into contact with his shadow and is instantly vaporized. Banton convinces Davey to engage the accelerator once he's inside. But once Banton enters the chamber, he realizes Davey is a government operative. X, however, kills Davey, then transports Banton to a secret research facility for examination and testing.