In Haven, a man is out mowing his lawn. He hears a shrieking noise and falls over, dead.
Two men are playing tennis on the courts. They finish their set and the older one complains that he hears a strange noise… and then collapses to the ground, dead.
A couple is washing their car when the woman complains about a shrieking noise. Her boyfriend doesn't hear anything, and stares in surprise when his girlfriend dies.
At the wharf, Duke, Nathan, and Audrey take Jennifer to one of Duke's warehouses and surround her with a police guard to keep her safe from William. Audrey figures that the book is the key to defeating William and that Jennifer can use it to send William back between worlds where he came from and keep him there. However, she figures that William will step up his plans now that he knows Jennifer has the book. Jennifer reads the first page of the book and repeats the riddle about finding the "heart of Haven," but none of them know what it refers to. Audrey receives a call about the three dead individuals and they figure that William has begun his new plan. Nathan and Audrey leave to check out the crime scenes while Jennifer explains to Duke that the Guard symbol in the book is fading in and out. He remembers that someone has a Guard symbol that also fades in and out.
At the tennis court, Nathan and Audrey talk to Gloria. She informs Audrey that all three victims died at approximately the same time. Nathan talks to the man's partner and confirms that he reported hearing something just as he died. William is standing nearby, watching the entire thing, and Nathan and Audrey confront him. He tells Audrey that he healed himself and thus her as fast as he could, and that now people will start dying. When Nathan prepares to arrest him, William warns that people will keep dying if he does. Nathan steps back and William tells them to follow him if they want to know how to stop the deaths. Audrey goes with him, telling Nathan that William can't kill her without harming himself, and figures that playing along is their only option.
Duke and Jennifer go to the Herald and figure that they have to send William back through the door he came through, trapping him. Getting to the point, Duke points out that Vince has a Guard symbol that fades in and out, just like the one in the book. Vince confirms that the tattoo has been fading in and out and pulls back his sleeve, and they realize that it's doing so in sync with the symbol in Jennifer's book.
As William strolls down the street, he tells her that he wants to free her real self from the shell of Audrey Parker. He repeats his claim that she was the one who created the Trouble now afflicting Haven and that he just tweaked it. William plans to show her who is responsible and then she'll have to give someone a new Trouble to fix things. When she does, Audrey will remember who she really is. As for fixing things, William explains that they often gave people complimentary Troubles to see how they'd interact. Since a sound-related Trouble is causing the deaths, Audrey will have to create a silence-based one to stop it. Audrey refuses, saying that she'll find another way, but William assures her that she won't. He leads her to the park and points out a couple tending to their baby inside the gazebo. When Audrey looks at the baby, she realizes that he has William's black handprint on him. The baby starts crying and a nearby person falls down dead.
Nathan and Audrey go to the home of the couple, Ben and Ashley Harker, and talk to Ben. He confirms that his son cried at the same time that the three people died, and then admits that he knows about the Troubles. The Harker family has been cursed with a Trouble that when they cry, people die randomly and instantly. The Trouble usually manifests at puberty when the children have enough control to learn to stop crying. As Ben goes to get something, Audrey tells Nathan that William wasn't the one who created the Trouble, but she avoids saying who did. Ben comes back with a dish inscribed with a family warning about their Trouble, and warns that he can't teach his four-month-old son Aaron to avoid crying. When his uncle, who had Down's Syndrome, couldn't learn, they cut his vocal cords to save lives.
Ben goes to check on Aaron and Nathan takes Audrey outside and asks what William told her. She warns that he may not want to know but Nathan insists and Audrey finally tells him that she's the one who created the Troubles, and that she loved William. She worries that she isn't worthy of Nathan's love because she's responsible for the Troubles. Audrey also tells Nathan what William said that if she gave someone a Trouble then she'd lose herself as Audrey Parker and become the person she was originally.
At the Herald, Vince tells Duke and Jennifer that the Guard symbol is a birthmark and that people in his family have had it since the founding of Haven. It designates the Teagues as the protectors of Haven, and Duke figures that the book led them to Vince because he knew what the heart of Haven was. Vince wonders if he's the heart, but Jennifer notes that the book would reveal more instructions if they solved the first riddle. She wonders what the second-born gets, and Dave admits that he's an orphan like her.
Nathan and Audrey try to figure out how Aaron's Trouble works and who will die, but have no success. Gloria arrives and explains that she's Ben's stepmother. She realizes what's going on and tells Nathan and Audrey that she researched the Harker Trouble but couldn't find any way to stop it. In 1901 the Trouble wiped out hundreds and the Herald covered it up by claiming it was an outbreak of Spanish flu. She realizes that they might have to kill Aaron to stop the Troubles, just like they killed the Troubled person in 1901, and vows to stop anyone who tries. Furious, Gloria tells Audrey to figure out a way to save her grandson. Nathan suggests that since Audrey is immune to the Troubles, she hold the baby in the hopes it will negate his Trouble. The Harkers bring Aaron out and Audrey holds him as he starts to wake up. He cries and Ashley collapses to the floor, dead.
As the EMTs take Ashley's body away, Ben admits that he can't cry for his wife and asks Nathan what to do. Nathan tells him to be strong and then gets a call confirming that another man died at a warehouse at the same time. Gloria's hard-of-hearing husband Lincoln arrives and hugs his wife, and they bring him up to speed on what is happening. He goes inside to watch his son while Ben anticipates that they have an hour and a half until Aaron wakes up and starts crying again. Nathan goes to check on the dead man at the warehouse while Audrey goes to the Herald archive to see if she can find anything about Aaron's Trouble. Once Nathan leaves, Audrey calls Duke.
When Nathan finishes checking at the warehouse, he finds William outside. William insists that he isn't the one responsible for the deaths and tells Nathan that when Audrey makes the right decisions, the deaths will stop. Nathan demands to know what's going on and what the connection is between William and Audrey, but William tells him that it's beyond his understanding and that all he wants is "his" Audrey back. When Nathan threatens to kill him once he breaks his connection to Audrey, William punches him hard and Nathan realizes that he can feel his touch, just like he can feel Audrey's. Nathan warns that William can't turn Audrey into something he isn't, but William points out that she's stalling because she thinks he can.
Duke tells Jennifer about Aaron from Audrey's call and she tells him that she'll be safe under guard while he helps Audrey. They kiss and Duke leaves for the Herald.
As Audrey goes through the old Herald issues, she finds one from 1901 that shows her in a photo in another of her past lives. Duke arrives and Audrey admits that she can't figure out a way to stop the Trouble, and that none of her past selves ever did either. With only 25 minutes left until Aaron wakes up, they're running out of time. Duke works out that Audrey's original self created the Troubles and Audrey tells him what William wants her to do. Realizing why she really summoned him there, Duke refuses to approve if she does what William wants, and warns that it will corrupt her. Nathan arrives, overhearing them, and tells Audrey to do it. He's confident that she can hold onto her Audrey Parker self, but Duke warns that the risk is too great.
Audrey finally goes to the field that William claimed was their favorite spot and finds him waiting for her. She threatens to kill the baby rather than give someone else a Trouble, but William realizes that she's bluffing. He assures her that even if she kills Aaron, he'll go after the Harker family's other young children and activate their Trouble early as well. Audrey realizes that he'll do it and agrees to give into his demand. Satisfied, William explains that three things are required to give someone a Trouble. First Audrey has to imagine the Trouble she wants to bestow, then she has to find a suitable person to match her intention. Finally she has to use one of the black spheres, crush it in her hand, and touch her intended victim. Audrey says that she'll do it, taking one of the black spheres from William, but says that she'll do it without him.
Audrey returns to the Harker house and tells Nathan and Duke what happened. Concentrating, she tries to work out the intention of the Trouble she wants to inflict. Nathan explains that the man at the warehouse said he heard a noise just before he died, and they figure that a silence-inflicting Trouble will do the trick. Now they need someone who matches up with the intent, and see Lincoln nearby. Remembering that he's deaf, Audrey figures that he would be suitable. They tell him and Gloria about their plan and Lincoln agrees to save his grandson.
At the warehouse, the Teagues argue over checkers. As Jennifer comes over, she notices Vince's Guard symbol moving and they realize that the pointer shifts as he moves, pointing in a specific direction: the Haven lighthouse.
Audrey crushes the black sphere in her hand and touches Lincoln. At first nothing happens, but then suddenly random noises burst out in the room. They wake up Aaron, who begins crying, and Audrey takes the baby outside. Ben goes with her and tries to comfort his son, while Audrey receives a text message reporting five more deaths. William comes up and asks if Audrey remembers her true self, and is disappointed when he realizes that she is still her Audrey persona. He gives her the box with six black spheres this time and explains that inflicting Troubles is more of an art than a science, but assures her that she's close. Once William leaves, Duke comes over and tells her to hand over the box. He's realized that Audrey lied and that she started to revert back to her original self… and she liked it.
As Vince opens the lighthouse door, he figures that they've reached the heart of Haven. The lighthouse, in one form or another, has always stood on the spot. When they go in, they find no way up to the hatch. However, Jennifer sees a trapdoor in the floor that the Teagues can't. She touches it and it becomes visible, and they descend to the floor below.
Audrey admits that she felt a jolt of true evil when she gave Lincoln his trouble, and that a part of her liked it. Duke warns that once she gives in, she won't be able to resist or even want to resist. He refuses to let her do it but Audrey insists that she can hold out. Before they can resolve the matter, Ben comes over and asks Duke to kill him, ending the Harker Trouble.
Vince, Dave, and Jennifer explore the cellar and find a tunnel leading into a large room. There's a geometric shape on the floor with four indicated positions. The book reveals a new instruction, saying that four specific people must stand in the spots. However, it doesn't say who.
Duke asks Ben if he's sure, and Ben explains that one of Duke's ancestors killed Gloria's ancestor, ending the Trouble that afflicted her family. Ben is sure, and Duke tells him to take Aaron inside. Audrey realizes that Duke wants her to use her ability to give him his own Trouble back, which will allow him to carry out Ben's wish. She objects but Duke says that he's willing and Ben is volunteering, and their only other option is to kill Aaron and let the Harker Trouble continue.
Inside the house, Ben tells his stepmother what he wants Duke to do. Audrey comes in and Gloria, furious, asks if she plans to kill her family one by one. She tells Audrey to think of a different way, but Ben points out that Gloria told him about how it was a blessing when Duke's ancestor ended her family's Trouble. He thanks Gloria for raising him and teaching him how to stop his Trouble from killing others, and wants to make things so that Aaron can cry without fear.
Jennifer calls Duke and has him come to the lighthouse. She tells him what they've discovered but Duke says that he has to go back. Jennifer wonders why he wants to be the hero again, and Duke explains that since Audrey knows how his Trouble works, she can get it right on the first try. He assures Jennifer that they will be fine once he's done and they can have a life together. Jennifer doesn't believe it, but finally gives in and tells him to do what he has to.
When Duke returns to the Harker house, he tells Audrey to get it over with. She crushes a black sphere in her hand and prepares to touch his chest as the others look on.