In the next episode of "The X-Files," Fox Mulder (David Duchovny) and Dana Scully investigate some mysterious deaths supposedly caused by the victims' doppelgangers.

The trailers and promotional photos of the upcoming installment, which is titled "Plus One," were just recently released, and they show Mulder and Scully at the scene of a murder and examining the evidence. Apparently, the victim got killed in his house by his own sword. The two then ask the medical doctor for any testimonies regarding the murders.

In a strange turn of events, the doctor replies, "The victims all saw their doubles." Interestingly, the killer turns out to be victim's look-alike who takes out the sword and slashes him to death. It seems that the agents are venturing into unexplained phenomena and have to keep their wits about them.

"Clearly, there is a dark influence set loose in this town," Mulder says to his partner. Mulder has always been more open to fringe science and conspiracy theories.

However, it seems that Scully may be succumbing to strange theories as well. She replies to him, "You mean evil." Mulder looks back at her with approval.

Later, when Scully takes a nap, she suddenly dreams about herself who turns out to be her evil doppelganger. Then in her car, she sees it again in her rearview mirror which gives her a fright. It remains to be seen what causes the doppelgangers to happen.

In the last episode, Mulder and Scully discovered that Erika Price (Barbara Hershey) had created a digital world, where humans could upload their memories and personas to this mainframe when they died. The agents destroyed it in the end because they figured that it was morally wrong.

"The X-Files" season 11 episode 3 will hit the airwaves on Wednesday, Jan. 17, at 8 p.m. EST on Fox.