With their five-year-old son Jacob as best man, Elizabeth Welles and Mark Bennett finally get married after eight years together.Seven years after Jacob's death in a tragic car accident and six years since their divorce, Mark continues his life alone while remarried author Elizabeth promotes her latest book.Mark receives word that his and Elizabeth's former home, which became a rental property, was seemingly trashed by its latest tenants. Mark stops by the house to clean up and meets next-door neighbor Amy and her young son Dash.Mark hears footsteps in the empty house. Janice Trejada comes to the door looking for previous tenants Peggy and Steve. Janice explains to Mark that she is a psychic medium who was doing consulting for Peggy.Mark calls Elizabeth to tell her he wants to sell the house. Doors suddenly slam on their own. Additional paranormal activity and an apparent vision of his dead son lead Mark to believe Jacob may haunt the home.After angrily confronting Amy about Dash possibly being the boy in his house, Mark comes face to face with a vivid vision of Jacob playing with his toys. Mark tries touching Jacob, but is painfully shocked. Jacob asks where Elizabeth is.Mark goes to see Elizabeth, who now raises stepdaughters Emma and Isabelle with her new husband Smith. With some animosity still between them, Mark is unable to convince Elizabeth to revisit their former home.Elizabeth later shows up at the house unexpectedly. Elizabeth sees Jacob too, but violently strikes Mark and storms away under the impression that Mark may be playing a drunken prank.Dash finds Mark passed out. Dash tells Mark about his broken family. Mark tells Dash that his son Jacob died in a car accident for which Mark feels responsible.Mark meets with Janice to ask about the ghost. Janice says it is up to Mark to discover what Jacob wants in order for Mark to send the boy back to the other side.When Jacob asks after his mother again, Mark returns to Elizabeth. Mark convinces Elizabeth to come back to the house.Elizabeth realizes the vision of Jacob is real, although she too is unable to touch him. Elizabeth and Mark begin a routine where she spends days in the house with Jacob while Mark stays there nights and weekends.Mark's boss Daniels discusses Mark's distraction at work and extended absences. Mark quits his job to spend more time with Jacob, which concerns Elizabeth.Elizabeth and Mark get into an argument about Jacob's death. Elizabeth blames Mark for swerving to avoid a dog while Mark blames Elizabeth for not buckling Jacob's seatbelt. Light bulbs suddenly shatter to interrupt their shouting. Jacob tells his parents that he wants them to be like they were before he died. Jacob makes Mark and Elizabeth hold hands and read him a story.Mark and Elizabeth reconcile. The two of them continue alternating spending time with Jacob in the house.Elizabeth becomes startled by supernatural activity caused by an unseen entity. Mark finds Elizabeth with a bloody nose.Jacob asks Mark why Elizabeth doesn't sleep in the house. At her home, Elizabeth shows the photo album from her first wedding to one of her stepdaughters.Mark and Elizabeth have another introspective conversation about Elizabeth's book and coping with Jacob's death. Jacob has his parents hold a funeral for a bird that flies against a window.Amy asks Mark and Elizabeth to watch Dash. Jacob expresses envy when he sees Mark playing with Dash outside.Elizabeth screams when she sees Jacob interacting with an unseen female presence. Mark finds Elizabeth passed out.Mark and Elizabeth continue growing closer as they dance together that evening. Amy interrupts a romantic moment to retrieve Dash.Mark asks Jacob about the other entity. Janice comes to the house and explains that Mark has to send Jacob back in order to close the otherworldly door. Elizabeth expresses anger over the suggestion of sending Jacob away.Mark and Elizabeth realize Jacob can go outside. The three of them then enjoy a day at the beach together.Elizabeth falls asleep at the house while reading Jacob a story. Mark and Elizabeth rekindle their love for each other, kiss, and have sex.Smith shows up the next day to confront his wife about being with her ex. Elizabeth goes after Smith when he drives off.Jacob tells Mark that he took off his seatbelt before the car accident. Mark realizes Jacob came back so his parents could forgive each other for the accident not being their fault.Elizabeth returns to the house and sleeps with Mark again. Mark visits his elderly father Lenn, who suffers from dementia.Elizabeth sees a vision of Jacob with her dead mother, whom Mark cannot see. Mark rushes Elizabeth to the hospital when she gets another bloody nose and faints.Amy, who is a nurse at the hospital, takes Mark to see Elizabeth after she recovers. Elizabeth tells Mark her condition was caused by quitting her anti-depressants cold turkey.Mark comes home to find Jacob playing with his new toy train set. Jacob tells Mark he went on a trip and Elizabeth is coming with him next time. Realizing she may be dying, Mark confronts Elizabeth for the truth about her diagnosis. Elizabeth confesses that she has terminal leukemia. Mark tells Elizabeth what Jacob said about his seatbelt.Mark, Elizabeth, and Jacob go to the beach as a family again. Mark repeats his wedding vows to Elizabeth during another intimate moment.Elizabeth goes into the hospital. Mark comes home to find the train running, but no sign of Jacob. Elizabeth and Jacob are seen embracing in a white light in her hospital bed.Mark is seen at the beach near Smith and his two daughters following Elizabeth's funeral. Dash greets Mark when he returns home. Following a cordial conversation, Mark invites Dash inside the house to play with Jacob's train.