Will and Susan Thomas, with their teenage son Logan, are moving into a house inherited from an elderly aunt. Will reminisces about visiting the house when he was a child and remembers how the house was full of laughter. Logan retorts that the house is full of creepy stuff and Will admits that his aunt was eccentric.
Going upstairs, Logan finds a boy's room which has been preserved throughout the years. As he enters the room, an eerie breeze blows the curtains and Logan is drawn to the window. Looking out, he sees the figure of a young boy, around ten years old, standing on the very edge of the dock, looking up at Logan. Logan rushes outside, but the boy falls from the edge of the dock into the water. Logan peers over the edge, but there is no sign of the boy.
Disturbed, Logan returns to the house to look for his parents, but he is distracted when a vase begins to shake in the front room. As Logan moves for a closer look, a large bookcase begins to shake and topples over on to Logan, knocking him unconscious.
Alex is in bed, experiencing a disturbing dream about her grandmother, Rose. Rose tells Alex that she loves her and will always be there for her, while urging Alex to help 'them'. Alex awakens distraught.
Next morning, a clearly upset Alex is sitting at the breakfast table lost in her thoughts, when Nick comes back from his morning run. Noticing that Alex is preoccupied, he asks her if she is all right. Alex tells him that she's been dreaming about her grandmother and Nick asks if she wants to talk about it. She says no and says she just needs a break. At that point, the phone rings and Nick answers - it is Susan Thomas asking for Alex. Susan tells Alex that she knew Grandma Rose in Louisiana and the previous night Grandma Rose called, urging her to contact Alex about the strange happenings in the house. Alex looks shocked.
Alex and Nick arrive at the Thomas' house and are told about the bookcase incident. Nick asks if Logan is okay and Will assures him that he is fine. Will believes it is simply an accident, but Susan argues that the bookcase stood in the same spot for 50 years until now. Will dismisses his wife's worries as 'Louisiana superstition'. Nick asks to look around the house and he and Will leave Susan and Alex alone. Susan tells Alex that she feels as if she knows her since Grandma Rose was so proud of her and that Grandma Rose called just after Logan's accident. Alex argues that it couldn't have been Rose since she passed away almost a month ago. Susan is stunned by the news.
Upstairs, Will tells Nick that they inherited the house from an aunt and since he lost his job back home, it was a chance for a new start. When Nick asks if Will's aunt had family of her own, Will tells him that she had a son but he must have not wanted the house. They go into Logan's room, but find it empty.
Outside, Logan is standing at the edge of the dock, peering into the water. He crouches down and sees the shadowy image of a boy floating beneath the surface. At that moment, his father touches him on the shoulder, startling him. Will tells him he should be resting in bed and introduces him to Nick who comments that he thought Logan was about to fall in. Alex and Susan arrive and Alex reaches out to shake hands with Logan, telling him that he was friends with her grandmother. As Alex grasps Logan's hand, she begins to experience visions of Logan pushing her into the water and holding her beneath the surface. Logan's face eventually transforms into the face of the young boy. Noticing her strange reaction, the Thomas' ask her if she is okay and Alex dismisses it as a headache. Nick stays silent.
Back at the car, Nick asks if it was really Rose who called the Thomas'. Alex shrugs, but insists that something happened there and tells Nick about the vision on the dock where Logan was apparently drowning her and then changed into someone else. She says that the other boy was full of rage.
Nick talks to Derek on the phone, assuring him that Alex is okay.
Upstairs, Alex is in bed, dreaming again about her grandmother. In the dream, Alex urges her grandmother to live, but Rose says good-bye and urges Alex to save 'him'. The figure of the young boy on the dock suddenly appears, telling Alex that she can't save 'him' because he is going to make 'him' pay.
The next morning, Alex tells Nick about the boy and Nick assures Alex that if a boy died at the house - they'll find him. Alex goes upstairs to take a bath while Nick does some research on the internet. He uncovers a story about ten year old Matthew Thomas who drowned alone at Storrs Pond.
Logan is raking leaves in front of the house when he hears the voice of a young boy calling for 'JD'.
In the bath, Alex begins dreaming and hears her grandmother say:
You are measured by the good you do in life. Remember that, Alex. You want to be able to hold your head up when you come to the end of your journey.
Alex agrees and Rose continues:
You've got to stop worrying about me. Too much to do. You've got to help the boy, before it's too late.
Alex awakens from the dream.
Logan walks to the edge of the dock, asking who is there. As he turns around, hands reach out of the water, grasp his ankles and pull him into the water.
Still in the bath, Alex begins to have trouble breathing as the boy is held under the water.
Logan struggles fiercely in the pond and screams for help. His father hearing his cries from the house, rushes down to the pond. He pulls Logan from the water and begins CPR. Logan revives.
As Logan revives, Alex is able to breathe again.
Later, Alex is looking out the library windows as Nick enters. Nick tells her that he just called Will and she was right - Logan did almost drown. Alex insists on seeing Logan, but Nick says he's being kept overnight at SF General for observation. Nick asks Alex to tell him what happened. Alex says that she was there and felt everything Logan was feeling - his terror and his suffocation. She saw everything as it happened and that Rose was there too. Nick asks Alex if she thinks she may have inherited Rose's power and Alex agrees Rose is trying to tell her something about the boy who is trying to kill Logan. Nick shows Alex a copy of the news article he found on the internet and Alex recognizes the boy from the picture. Nick tells her that the boy is Matthew Thomas and he was ten years old when he drowned in Storrs Pond. Alex looks thoughtful and says, 'How do you like it?' She remembers that the boy repeated that phrase over and over again while he was holding Logan under the water. He also repeatedly called Logan 'JD'. Nick pulls out another page and says Matthew was pulled from the pond by his older brother - Jeffrey David. Alex notes that JD was seventeen when Matthew died - the same age as Logan - and wonders if Matthew is mistaking Logan for his brother. They have to find JD. Nick says he has a friend in Social Security helping him track JD down. Alex asks his name and Nick smirks and says 'Dominique'. Alex rolls her eyes. Nick says they should have information in a couple of hours and in the meantime they can visit Logan.
SF General Hospital
Logan is asleep in bed hooked to monitors, as Alex stands over him. Outside the room, Will tells Nick that he doesn't know what happened as Logan is an excellent swimmer and that the water was only waist deep. He thought Logan must have hit his head but the doctor found no evidence of a head injury. Alex asks if Logan said anything about the incident and Susan says that he remembers nothing. Alex tells them that it is possible that there is something going on which directly involves the family. Nick asks Will if he remembers Matthew Thomas and Will says he drowned as a child. Alex asks how much Rose told them about what she does in San Francisco and tells the Thomas' that she thinks Matthew's ghost is haunting the house and he is responsible for Logan's accidents. Will laughs in disbelief. Alex presses him by asking if his aunt ever spoke to Matthew after his death. Will scoffs that his aunt was mad and she spoke to her cat. Nick asks if Jeff ever spoke about strange occurrences after Matthew died. Will tells them that Jeff left to join the army soon after Matt died and he hasn't seen him in years. Nick's phone rings and he moves away to answer it. Alex maintains that she saw Matt and felt his rage. Will starts to get angry and tells Alex that she should leave, but Alex insists they move out of the house until the situation is resolved. Will retorts that they can't afford to live anywhere else and he and Susan leave. Nick returns and tells Alex that he has Jeff's last known address.
Nick and Alex enter a bar and ask the bartender if he has seen Jeff Thomas as his landlady believed he would be there. The bartender points him out. Nick and Alex ask Jeff about Matt's drowning at Storrs Pond. He gets up and heads towards the bar, clearly upset by the questioning. He and Nick get aggressive and Alex tells Nick that she will handle it. Nick backs off, but continues to watch Jeff closely. Alex buys Jeff a beer and starts to question him again about his brother's death. Jeff confirms that he pulled his brother from the pond and left soon after to join the army. Alex asks if he was running away from something and whether strange things were happening at the house. Jeff angrily denies everything and warns Alex to back off. Alex tells him that he is lying; he knows his brother's spirit is still in the house and that his mother spent the rest of her life trying to comfort Matthew. Jeff roughly pushes Alex away and Nick steps in between them , punching Jeff in the face. The regulars in the bar move to help Jeff, but the bartender intervenes. Alex tells Jeff that his cousin Will has moved into the house and Matt is intent on taking his revenge out on Logan. Jeff tells Alex to get 'the hell out' of the bar and she leaves, pulling Nick after her.
Outside, Alex states that she knew by his eyes that he wasn't going to tell them anything despite knowing the truth and that made her mad. Nick maintains that the only way to get the truth out of a guy like Jeff who has been running away for 30 years, is to slap it out of him rather than sweet talking him. When Alex gives him a strange look, he insists he didn't mean that literally.
SF General Hospital
Alex decides to stay and watch over Logan. Nick asks if she wants him to stay too, but Alex says no and apologizes to Nick for her behavior. She says that she's finding it hard dealing with her grandmother's death and she feels guilty for not being able to stop it. Nick tells her that some things just happen no matter how hard you try to stop them. Alex thanks him for caring about her and Nick says she's going to ruin his reputation, while leaning over to kiss her on the cheek.
Jeff pulls out an old photo of himself and his brother and stares at it.
SF General Hospital
Alex falls asleep in the chair next to Logan's bed and starts dreaming. In the dream, Matthew enters the room and gazes malevolently at Logan in the bed. Alex wakes and approaches the bed, but it is Matthew who looks back at her instead of Logan. Waking up for real this time, Alex sees that it is Logan in the bed and not Matthew.
Next morning, Logan awakes and Alex asks if he remembers anything about the accident. At that moment his parents arrive and ask Alex what she is doing there. Alex says she thought it would be best if she stayed there and urges them to come and stay at the Legacy house, but they refuse. Alex tries to persuade them that Logan's accidents were more than mishaps, that there is a real danger at the house and Jeff has witnessed it too. Will is angry when he discovers that Alex has spoken to Jeff and asks her to leave.
Nick asks Alex how things went at the hospital and when she says they think she's a crackpot, Nick says you can't blame them since they are talking about ghosts. Alex begin packing and a bemused Nick asks if she is running away from home. Alex tells him she had another dream and she knows Logan is in danger and she will sleep in her car in front of the Thomas' house if it means helping him. Nick tells Alex that they are dealing with a water spirit - an angry, unsettled soul. The longer the spirit remains the more powerful it will became and the more damage it will cause. Nick's phone rings - Jeff Thomas is at the front gate asking to see them.
The Thomas' arrive home with Logan.
Jeff apologizes for his actions in the bar, prompting an apology from Alex as well. Jeff confesses he was there when Matthew died. He loved him and looked out for him, but Matthew could be a real pain at times and got all their mother's attention. One day, he was drinking at the dock and Matthew threatened to swim out to the float in the middle. Matthew started to get into trouble and called for help, but Jeff thought he was faking it and ignored him. When he eventually realized that Matthew wasn't faking - it was too late. When he pulled Matthew out of the water, he was dead. He made himself believe that Matthew had been on his own and he had found him already dead, but strange things began to happen. After seeing Matthew outside the window, Jeff promptly left the next day to join the army.
Logan goes into his bedroom and discovers that the bedroom has been transformed back into Matthew's old room. Logan believes his parents are playing a trick on him, but when he goes to confront then - Matthew appears and tells him it is time to pay. Will tries to talk to Matthew but Matthew raises an arm and throws Will and Susan across the room. Logan begs Matthew not to hurt them and says he will do whatever Matthew wants.
Out on the dock, Matthew orders Logan to swim towards the float and back again. When Logan hesitates, Matthew uses force to throw him into the water and orders him to swim or he'll hurt Will and Susan. Logan has no choice but to comply.
Alex and Nick arrive with Jeff and begin to search for the Thomas'.
Logan reaches the float, but as he swims back he gets into trouble and calls for help. Matthew yells that he is faking it and taunts Logan with, 'Is that the best you can do?' Alex arrives and asks Matthew what he is doing. Matthew says he was hurt and now it is time to hurt Logan. Alex tells him that he doesn't want to do this and shouts to Nick that Logan is going to drown. Matthew throws Alex aside, as Nick rushes into the water to save Logan. Matthew yells at Nick to leave Logan alone, but before he can do anything, Jeff arrives and distracts his attention away from Nick and Logan. Matthew attacks Jeff, accusing him of letting him die. Matthew turns back to Nick and Logan, but Jeff distracts him by admitting that it was all his fault and he's to blame. Matthew's rage dies and he calls out to Jeff. Jeff reaches for Matthew and they hug. Nick manages to pull Logan out of the water and Matthew's spirit ascends, finally at peace. Jeff thanks Alex - he is no longer running away.
Alex is writing her journal:
"Even in death my grandmother tried to help me. She helped me overcome my own grief and guilt, and gave me this gift. The sense to understand people and to try to help them. And by doing so, hopefully, a part of her will live on in me."
Alex sits on the bed, looking at a photo of her grandmother and says:
"I love you, Grandma. Sleep well."