Sam’s friend, Zach, is accused of murder. Sam offers to help out by checking up on his sister, Rebecca. Rebecca claims her brother could not have committed the murder because he was with her at the time of the murder. But all the physical evidence points to Zach being at the scene of the crime. Could Zach have been at two places at the same time?
St. Louis, MO
A man is preparing to torture a bound woman with a knife as police assault officers burst in. The man slips by them as they move in and find the woman, still alive. She directs them to the departing torturer and they give pursuit. They catch him with the knife as he escapes, and it’s…Dean.
One Week Earlier
Sam and Dean pull into town and Sam is checking e-mails from his friends at Stanford. He gets word from Rebecca, who says his brother Zach is under arrest for killing a girl but both she and Sam believe Zach is innocent. Sam insists they go to St. Louis to help and Dean reluctantly agrees. They go to Rebecca, who is at her parent’s house – they’re in Paris. Rebecca reveals Zach came home and found Emily tied to the chair, beaten up and bloody. He called the police but they arrested him – they have a video from a security tape showing Zach coming into his home at 10:30, but he was with Rebecca until midnight. Sam claims Dean is a cop and his brother plays along with it.
They go to Zach’s house and Rebecca reveals someone had broken in and stole clothes a week earlier. The family dog is now extremely vicious and Rebecca confirms it turned violent around the time of the murder. Rebecca already got the tape and as they go to review it, elsewhere “Zach” is watching a businessman and his wife and doing a sketch of the man – “Zach’s” eyes briefly turn white.
The tape confirms what the police claim, that Zach is the murderer. After getting Rebecca out of the room for a moment, Sam point out that “Zach’s” eyes flashed white and that some kind of doppelganger is responsible. The businessman, Alex, returns home but his wife Lindsay doesn’t respond. Alex spots a bloody handprint and finds her tied up and bloody and begging him not to hurt her any more. He runs out of the room but his counterpart hits him with a baseball bat, knocking him out.
At 5:30 a.m. Dean and Sam go back to Zach’s house and look for a trail, since the killer never went out the front door and the police didn’t bother to check the back. They find a blood print then spot an ambulance going by. They check it out and hear about how Alex, a nice guy, killed his wife. Sam looks around for evidence while Dean decides it’s “their kind of problem” – Alex’s story is the same as Zach’s. Sam picks up a trail but it suddenly ends just like at Zach’s house – Dean thinks the monster went down.
In the sewers they find a mess of discarded flesh, skin, and goo, and Dean wonders if the creature sheds its skin. They head back to the car to get silver bullets, and Rebecca calls to tell them she knows Dean isn’t a Detective. Dean advises Sam to get used to not having any friends. They head back into the sewer and close in on the creature, finding another pile of discarded skin. The creature (as “Alex”) attacks them from behind, wounding Dean’s shoulder, and Sam chases off after it as it makes for the surface. They split up but no luck – the two join up but as they head back for the car, Dean’s eyes glow white.
Sam has a few doubts about Dean but “Dean” is able to answer his implied questions about their father and their past history. But then Sam draws a gun on him anyway, noting the wounded arm is no longer wounded and Dean took the keys with the wrong hand. “Dean” tries to bluff his way through but when it doesn’t work, he knocks Sam out. Sam wakes up and “Dean” slaps him around for a bit, then reveals that he was able to probe Dean’s memories, and that Dean resents Sam for going off to college. “Dean” goes on about Dean’s issues, then heads off to hit on Rebecca.
Dean wakes up in the creature’s lair while “Dean” talks his way into Rebecca’s house and explains the shapeshifter situation. “Dean” talks about how the creature was a hideous genetic freak, scorned by society, until it found a way to take on the shapes of others. Dean manages to scrape through his ropes and free Sam, while Rebecca gets angry when “Dean” starts to hit on her. When she tries to call the police he takes her captive but before he can go to work, we’re back at the beginning of the episode
Then “Dean” takes out one policeman with the knife and kicks around the others long enough to escape, but not before he takes a wound. In the sewers, the shapeshifter discards Dean’s form in a long painful process.
Sam and Dean catch a newscast broadcasting Dean’s appearance and go into hiding – they’re out of weapons so they need to get to Rebecca’s to get the car. They make it but the police close in and Sam gets arrested while Dean makes a break for it. Against Sam’s advice, Dean goes into the sewers alone and finds…Rebecca.
Meanwhile Sam is out of jail and goes back to meet with Rebecca…who is the shapeshifter. The shifter takes on Dean’s appearance again after tying up Sam, and plans to kill him so that Dean will have to be on the run for the rest of his life. “Dean” expresses his admiration for Sam and prepares to start cutting with the knife. Sam kicks him away long enough to slice the ropes and free himself, and the two of them fight. “Dean” finally gets the upper hand and is strangling Sam when the real Dean arrives and puts two silver bullets into the shifter’s chest.
Sam reveals what he does to Rebecca, who is more then willing to believe after seeing the shapeshifter at work. Rebecca asks Sam to call some time and he promises he will…but not for a while. Zach is cleared – the police believe a “Dean Winchester” is responsible and the tape was tampered with. The brothers head out and Dean apologies but recognizes that they’re both freaks, and they’re in it together.
Warning : May Contain Spoilers.