Sherri and her fiance Greg are jogging along a trail near the woods. Greg stops and goes behind a tree to relieve himself. Sherri hears him scream and rushes over to find him dead and a pair of lungs next to his body.
Duke visits Audrey at her apartment but she refuses to talk about the revelation that she may disappear when the Hunter meteor storm arrives. Duke says they have to soon because the Hunter is coming in 46 days. He realizes she has not told Nathan.
Audrey arrives at the murder scene and Nathan fills her in. The coroner confirms that Greg's lungs have been extracted but his body has no incisions, so it must be a Trouble. A man in the crowd takes photos of the crime scene.
The officers return to the station and Audrey notices Nathan has theater tickets in his pocket. He explains that he got tickets for a film not to be aired until a few months and invites her to join him when it is time. She realizes that she has no choice and tells him about the Hunter and how she may disappear in 46 days. Before Nathan can respond, the coroner walks in and reports that the lungs on the ground are necrotic and don't belong to Greg.
They interview Sherri but she says she already talked to Officer Tommy Bowen. There is no Tommy Bowen in Haven PD so Nathan puts out an APB for the apparent imposter. They get a call about a disturbance and head out of the Sellers residence. They arrive and find the man who took the pictures, Tommy, examining a dead man with a set of diseased kidneys next to it. They arrest him and find from his wallet that he's from Boston PD. Tommy tries to explain that he's looking for the killer too, but they cuff him. They hear a noise and find the dead man's sister Zoe upstairs, in shock.
They take Tommy and Zoe to the station. Zoe says her brother fought with the intruder to save her life. Claire comes in and asks Audrey if she's talked to Nathan about their relationship, but she says she's been busy and goes to her office, where Duke is waiting. He apologizes for upsetting her earlier but she says she told Nathan about the Hunter. Duke encourages her to try to fight her fate, just like he tries to fight his.
Officer Glen's nephew Mark visits the station. As Glen shows him around, Claire comes out of Zoe's interrogation room and asks for help because Zoe seems really sick. Zoe snaps out of her shock and looks wildly around.
Nathan confirms that Tommy really is from Boston PD and asks what he is doing here. Tommy explains that Paul, his partner in Boston, also had his organs extracted. A witness reported that the murderer wore a Haven baseball jacket so he came to Haven to investigate. Tommy threatens to call in the FBI, since the murderer is now an interstate criminal, but promises not to do so if they let him work with them to take the murderer down.
Mark screams and they run out to find Zoe attacking him, a lamprey-like tentacle extending from her mouth toward his mouth. Nathan and Audrey try to restrain her but she throws them off. Tommy knocks her out with the butt of his pistol, the tentacle retracting into her mouth as she falls. Tommy didn't see the tentacle because he was standing behind her, and figures Zoe was high on PCP. Nathan and Audrey figure she was the murderer, but Tommy says the person who killed his partner was a man.
Zoe is taken to the hospital. Claire reports that Zoe has gone into a coma and her organs are failing. The coroner reports that the lungs and kidneys belong to the same person. Audrey figures that the murderer's Trouble is that his organs progressively fail and he must regularly replace them. He seeks out people related to him to minimize the chances of organ rejection. Since Troubles are hereditary, any of his victims who survive his attack get their Trouble triggered by the shock and seek organs as well.
Mark's organs start failing as well and they question Glen, who insists that he and Mark are not related to Zoe. However, Glen admits that Mark's mother used a sperm donor. Tommy, not really understanding what the others are talking about, confirms that Paul's mother used a sperm donor from the fertility clinic in Haven.
Audrey, Nathan, and Tommy visit the fertility clinic and ask to review the staff and patient records. Nathan and Audrey talk in private and figure that the killer substituted his own sperm several years ago so that he would have a large supply of potential victims with compatible organs.
The killer, Harry Nix, goes to the local high school. He watches from his truck as a high school girl, Miriam LaCroix, leaves for the day.
Nathan and Audrey confirm that all victims so far had mothers who used the fertility clinic. They figure the killer uses the tentacle to regurgitate his old organs and extract his victims' organs through their mouth. Tommy catches the end of their conversation. Not being from Haven and having never heard of the Troubles, he figures they are nuts. Duke comes in, saying Audrey called him. Audrey says she wants Duke's help in rounding up the 29 other children who could be descended from the killer. Nathan protests, but they leave. Tommy demands Nathan tell him the truth.
Harry approaches Miriam and asks to burrow her phone. She's reluctant but eventually gives it to him.
Audrey and Duke see Harry attacking Miriam. When he sees them running up, he rushes to his truck and escapes. Duke warns that Miriam is going into shock as the attack triggered her Trouble.
Nathan tells Tommy about the Troubles, but Tommy says it is ridiculous. Tommy says all he cares about is getting revenge for his partner, and does believe that the killer is going after his illegitimate children, attributing this motive as psychosis. Audrey calls and reports Harry's license plate number. Nathan looks it up and confirms Harry's name and address, and Tommy confirms that Harry was a former employee of the fertility clinic.
Audrey and Duke go to the Nix home, but it is empty, and they figure he is trying to skip town, taking his family as insurance in case his organs fail.
Harry drives his wife Marjean and their three children, who think he's taking them on a road trip. He stops at the house of one of his illegitimate children, but realizes no one is home. Desperate, he tells Marjean he loves her and says he is taking their son Connor into the woods to relieve himself.
Nathan and Tommy meet up with Duke and Audrey after confirming that the Nix family disappeared the last time the Troubles were in Haven. Tommy is losing patience and wants to call the FBI, but Nathan says they won't be able to deal with a situation like this. Tommy agrees, saying he never liked the FBI.
As Harry walks Connor into the woods, he says his own father once did something similar, then attacked him. Harry killed him in self-defense, but then his life changed forever. He apologizes for missing Connor's last game, and says he will be fine.
The group catches up to the truck and Marjean tells them about Harry and Connor. They rush into the woods to find Harry attacking Connor with his tentacle and tackle him away. Tommy sees the tentacle and is shocked, realizing Nathan was telling the truth. Harry collapses from his injuries and failing organs, crying and pleading that he doesn't want to die. Duke sees that Connor is going into shock as his Trouble activates. Audrey tells Nathan and Tommy to take Connor back to his family. Nathan realizes what she is planning and grimly nods.
Duke realizes Audrey wants him to kill Harry to eliminate his Trouble. He refuses, saying he is not a killer. Audrey says they have no choice, she's weighed every possible option, the only way to save all of Harry's offspring is for Duke to kill Harry, so Duke's Trouble can eliminate Harry's. They don't have much time, as Harry is about to die. Duke still refuses and Audrey angrily walks away.
Later, Audrey meets Nathan, Tommy, and the coroner at the morgue, where all of Harry's dead victims have been brought in. Tommy admits that the Troubles are real, and figures he can't tell anybody. Nathan says if he ever wants a job in Haven PD, he is welcome. Tommy leaves, and Nathan shows Audrey one more dead body. A woman who was shot in the back of the head with a bolt gun and had her nose removed. They confirm that Roslyn Toomey (see "301
") was also killed with a bolt gun. They figure that Audrey's abductor did it and wonder why he would do such a thing.
That night, Nathan approaches Audrey at the station and insists that they should talk. He wonders why she is giving up and asking Duke to kill Troubled. Audrey angrily notes that he didn't tell her about getting the circular maze tattoo. When Nathan explains that he did it to protect her, she tells him that she doesn't want his protection. Audrey tells Claire what happened. Claire realizes that Audrey is pushing Nathan away in an attempt to ease his pain when she disappears. Claire wants to discuss it further, but Audrey gets a call and leaves.
Duke is at an empty The Grey Gull and is miserably drinking glass after glass. Audrey comes in and reports that all of Harry's surviving victims have gone back to normal. Duke admits that he couldn't allow Connor and the others to die, so after Audrey left, he clamped his hand over Harry's nose and mouth until he suffocated. As Harry died, he coughed up blood into Duke's hand, who absorbed it and made his eyes glow silver briefly. Extremely upset, he walks away from Audrey without a word.
At his hotel, Tommy is getting out of the shower when he hears someone forcing the door open. He grabs his gun and prepares to face the intruder. Later, Tommy drives into the woods. He calls someone and angrily says he will stay in Haven rather than go back to Boston and get killed. He starts burying a body that is wrapped in a trash bag.