The captured boy lies restrained in a semi-reclined examination chair. He appears fearful, agitated and the tentacle protruding from his abdomen is flailing about wildly. In order to relax the boy, Will asks the Big Guy to release him from his restraints. Henry, the tech guy, comes in and gives Helen the analysis of the goo she extracted from the boy's victims. The radiation traces reveal the point of origin was Chernobyl in the Ukraine, where the boy's parents probably came from. Magnus is appalled at Henry' lack of sympathy for the boy ("The kid sucks brains! … Not that I'm being judgmental."). Henry also tells Helen that a prostitute was found murdered near the docks and Helen seems unusually interested. She asks Henry to send her whatever info he has. Leaving, Henry runs into Ashley by the elevator. She's going out, despite her mother's wishes: "I'm just going out to get some, uh … feminine products." "Yeah", says Henry, "feminine like a crate of Uzis?" Ashley, knowing that Henry can't resist, hits the down button saying "Dude, you want me to get us some toys, or what?"
Will is getting the hang of things with the boy. His dangerous appendage only reacts when the boy feels threatened. If Will doesn't show fear, it isn't aggressive. The boy reveals that his name is Alexei and tells Will his background story: he used to live with his Ukrainian parents, who tried to protect his secret, but then another family adopted him and they were afraid of him. Despite trying to stop it, there was so much fear that he couldn't control his tentacle. Will realizes the appendage is a defensive mechanism with a mind of its own and that the murders were not Alexei's fault. Later, Magnus receives the video of the prostitute's murder and recognizes her assailant. Meanwhile, Ashley's meeting with her weapons dealer is interrupted when they are attacked by the murderer.
Talking on the roof of the Sanctuary, Helen says that Will first came to her attention when he was eight years old - after telling everyone that a monster had killed his mother. Although nobody believed him, it was the truth. Later, Will managed to convince himself that it was an illusion, but that primal trauma fueled his study of the mind and perceptions. Will asks for a reason why he should help her, help creatures who "took everything from me" but Helen refuses, telling him that it's his choice and that "In the end, it's … a massive leap of faith."
After a fight in which, for once, she was the weaker combatant, Ashley and Sylvio manage to capture as yet unnamed Druitt ("Just someone new in town."). Henry helps her bring him to the Sanctuary and they put him in the 'shoe', the maximum security level. However, his "capture" was only a ruse to gain entry to the Sanctuary and he escapes before Henry can lock him up. Druitt seizes Henry and orders him to shut down the EM field, since he cannot teleport through it. Henry shuts down the field and Druitt shoots him with a stun gun.
Magnus finds out from Ashley that she ran into a "superfast" tall guy with a similar accent to her mom's ("only, uh … more evil."). Helen knows they're in danger. Suddenly, Druitt appears, greeting Helen as an old friend. Helen calls him by his first name - John. Then Druitt grabs Ashley as a hostage and teleports her inside a shoe cell housing a dangerous creature. Druitt tells Helen that he's here for her blood, which he needs in order to survive, and that Ashley won't be harmed if she helps him - which she's done once before. Helen claims she could find a cure for him but Druitt wants none of it, only her blood. He is angry that she clearly hasn't told Ashley the truth about him - that he's Ashley's biological father - and enraged when she reveals that she told Ashley her father was dead. Incensed, Druitt threatens to tell her the truth.
Helping Henry, Will and the Big Guy also discover Ashley trying to fight off a violent creature in one of the cages. They attempt to rescue her but Ashley is wounded and the Big Guy is hurt in the process. Meanwhile, Helen gives Druitt a syringe filled with what she says is her pure blood. He injects himself with it, only to discover that she tricked him. He begins to convulse and teleports away. Back in the cage, Will figures out that the creature doesn't like light and manages to fight it off until Magnus and Henry arrive and help them all escape.
The next morning, Ashley thanks Will for saving her life, and admits she might've underestimated him. Will goes to see the Big Guy, who is recovering, and tells him that only a few days ago, he thought the Big Guy was the stuff of nightmares, but he now realized that maybe there were no monsters. But the Big Guy, speaking to Will for the first time, tells him that there are indeed such things as monsters.
Will visits Helen and tells her he knows she withheld the truth from him. He now remembers that she was there the night his mother was murdered. Helen assures him that she tried to save his mother, but could only manage to rescue him. Will says that Helen's age at the time does not add up. In addition, he discovered that their recent guest, John Druitt, was a prime suspect in the Jack the Ripper case in 1880s London. Helen tells him that Druitt was one of her first patients and admits to being 157 years old. She reveals that she gave Druitt her blood to prolong his life because he was dying, but something went wrong. In a flashback to 1880s London, Druitt accosts a prostitute named Molly, but Helen shows up and says it ends here. Druitt introduces Helen as his ex-fiancée. He grabs the prostitute and says he has already killed seven others. Helen tells Druitt that his power is driving him mad and points a gun at him. Druitt slits the girl's throat and teleports away before Helen's bullet reaches him.
Back in present day, Helen tells Will that she has spent the years since then trying to undo her mistake. Will gathers from her story that Druitt is Ashley's father. Helen confirms it, saying that she kept the embryo frozen for over a century, until she could bear the loneliness no longer. She brought it to term, believing Druitt was gone, but he survived because of her blood. Will agrees to work with her, under the condition that she is always straight up with him. Magnus responds by saying that she has just trusted him with her "deepest, darkest secret". Will says he needs to know the entire truth : "You open this place up to me - every … monster, every room, everything that crawls, flies, teleports … If I'm gonna be of any use to you I gotta … I gotta a lotta catching up to do." Magnus agrees, promising him "the adventure of many, many lifetimes".