The episode begins in the fall of 2003, where a young woman is at a bar and it is closing time. She leaves the bar but her car wouldn't start. So she calls her mother for help. She is glad that her mother always comes running when she needs her. Just then a car pulls over and two men get out and start firing at the girl’s mother. They then chase her and she runs towards the woods. But then she trips and falls and the men are about to shoot her when a strange man lurking in the shadows, attacks the men and kills them. She catches a glimpse of her savior; but he doesn't look human! He quickly disappears.
We then hear the girl’s voiceover telling us that people told her that she saw things due to her concussion and that it wasn't a beast that saved her, but the men who killed her mother were indeed beasts. Cut to the present, we see that the girl, Catherine Chandler, is a detective in Special Crime. She arrives at the Stanwyck Hotel which is a crime scene- there is a dead body found in the women’s room. Catherine’s colleague thinks it is a robbery-homicide. Catherine then checks the security footage of the five- star hotel along with her boss, Joe Bishop. They see that the victim was already injured when she walked in to the hotel! They then identify the woman as Ashley Webster and she is the editor of a fashion magazine and her husband is Alex Webster, a fashion photographer.
They find prints on Ashley’s suit button and it is a match to a man named Vincent Keller; he is a doctor who then joined the military but he is dead. Catherine and her colleague then head to the hospital where Vincent worked. There they are told that Vincent joined the military after his brother was killed. Vincent wasn't very social; but the nurse tells them about his roommate, J.T. Forbes. Catherine and Tess then go to the address and find that Forbes lives in an old chemical plant. They talk to Forbes and tell him that Vincent’s prints appeared at the crime scene. But he mocks them saying that they need new fingerprint machines. We see that a man is hiding on the upper level and Catherine also feels that something isn't right. Forbes tells them that he has a bio-chem class to teach and the detectives leave. But Catherine is still feeling dubious about the whole thing at Forbes’ place. Forbes is indeed sheltering Vincent and Vincent “is” the beast Catherine saw that night.
When Forbes confronts Vincent, Vincent shows him the paper clipping of Catherine’s mother’s murder. Forbes gets worked up and argues with Vincent saying that he is breaking all rules. Vincent says he knows them as he was the one who made them in the first place. Forbes wants to know what Vincent was doing at the murder scene and Vincent tells him that the woman was in trouble and he was helping her. Forbes tells him that he needs to keep away from Catherine and if at all the word of Vincent being alive gets out, they will be dead-literally! Next, Evan Marks, the ME tells Catherine that the injuries are consistent with those of an attempted suffocation. But there are also marks that show someone tried to save her. There is a strand of hair found and he is processing it for DNA. Evan then asks Catherine out on a date. Next, Ashley’s ex-husband, Alex arrives at the station. He has an intriguing club stamp on his wrist. He says that he doesn't know where Ashley was last night.
He also asks them to check with Ashley’s assistant, Emily. Next, Tess and Catherine meet Emily. Emily tells them that the beauty editor, Chloe London was jealous of Ashley as she thought she deserved the editor’s position. Just then Evan arrives with the DNA report. It is a cross-species hair! Hmm… Tess calls Catherine and tells her that Forbes’ alibi checked out. Catherine still goes to the chemical factory. She finds Vincent there and confronts him. He tells her that he did not kill Ashley. She had hit her head and he tried to resuscitate her. He tells her that Ashley was poisoned as he could smell it. Evan calls and confirms the same; lethal doses of nicotine.
She then brings up his DNA and also sees the paper clipping about her mother’s death. She wants to know the truth. Just then Tess arrives and he begs her not to reveal that he is alive. She leaves with Tess. Next, she is looking for Special agent John Hernandez, the cop who was working on her mother’s case; but she learns that he has been transferred. Tess briefs the team that nicotine takes up to four hours to become toxic. They go to meet Chloe, the beauty editor and check beauty samples for nicotine. They also learn that Chloe got Ashley’s job. They then go through Ashley’s stuff and find that there is a pregnancy test kit with both strips missing.
She gets a call from an FBI agent saying that he got a call saying that she was looking into an old case. she meets him in the subway. He takes a look at the hair strand and she notices a strange man lurking behind. The FBI agent then draws out a knife and attacks her. a woman also joins them. The woman manages to throw Catherine on the tracks. Just then Vincent appears and “takes care” of the attackers. He then runs into the tunnel. Catherine follows him, leaving her phone on the tracks. She loses him and suddenly we see a train speeding towards her. Vincent appears out of nowhere and lurches her to safety. She looks at him and says “you are him”.
At the factory, Vincent tends to Catherine’s wounds. She wants to know about him. He tells her that after his brother’s death, he got into the military. He was then put into a special program called” Near-field” where they injected the soldiers with “vitamins” (that is what they were told) which altered their DNA. This made them stronger, faster and with heightened senses. But when the adrenalin kicked in, they turned into beasts. The project was shut down and all the super soldiers were eradicated; except him as he managed to escape. He and Forbes are now searching for an antidote. She tries asking him about what he knew about his mother? He tells her that the people who attacked her were from Near-field and now she is on their radar. He asks her to leave and that he can’t say anything else as he doesn't know.
Next day, Catherine finds the murder weapon. It is Catherine’s hair dye. The cops found three out of the four products Catherine had signed out before she died. So her dye was poisoned. Moreover, Evan finds bed bugs in Ashley’s bed which proves that her husband was fooling around with other women. The hostess who Alex was having an affair with tells them that she did not kill Ashley. Alex couldn't tell Ashley because of the stringent pre-nup as he could lose everything. But Joe tells Catherine and Tess that there was no pre-nup. Just then the FBI arrives and take away the dead bodies from the subway. The FBI guy warns Catherine not to interfere in their matters. She then goes to meet Vincent. She tells him that she lost her phone in the subway. He asks her to leave and cut all contacts with him.
She wants to know about her mother. he is furious and turns into the “beast” and asks her to leave and she quickly does as she is told. Next, Catherine meets Alex and tells him that they know about all his affairs and the “pretend pre-nup”. She wants a list of all the names of the women he was having an affair with. Next, they meet Emily. They tell her that they know about her affair with Alex and also that she was the one that signed for those products for Ashley. They tell her that she was the one using the pregnancy test. She tries to blame Chloe. Catherine tells her that there was no pre-nup and Alex lied to all his girlfriends, including the one he was with on the night Emily killed Ashley.
Her dreams of running into the sunset with Alex are now shattered. Emily is arrested. Next, Tess confronts Catherine about her recent actions. But Catherine doesn't say anything. Tess then returns Catherine’s phone to her which was found in the subway. Evan tells Catherine that he would go with her as her date, to her father’s engagement party. Catherine goes to Vincent and tells him that she feels that she is the reason that her mother is dead as she had called her for help.
Forbes is shocked that these two met. Vincent tells her that those guys were already tracking her mother; he doesn't know why. Catherine’s voiceover then tells us that she is relieved that she is not crazy; she was saved by a beast! And now they have to safe each other. We then see Vincent on a perch, watching her through the window. The episode ends.