Alice Darrow's terminally-ill husband Michael whispers "I'll come back" just before he dies. Puzzled but determined to get on with her life, Alice starts to see subtle signs that her husband may be trying to communicate with her from beyond the grave. Alice's fear is magnified by the guilt she feels about having fallen in love with another man before her husband passed away. Steve is a warm, supportive acquaintance who comforts Alice in her grief and is clearly interested in becoming more than just her friend. Alice confides in Steve, telling him that she doesn't believe in the afterlife: ″I think when life's over, it's over.″ A woman at Michael's memorial service tells Alice she had a dream about Michael, and that he was very anxious to tell her something, although she couldn't quite hear him.
As Alice starts developing a new romantic relationship with Steve, strange occurrences and visitations begin to worsen. Following a blackout in her office, Alice sees a strange glowing light on her computer screen that resembles a human face. The word ″kill″ appears scratched on Michael's desk, and a note stuck on Alice's computer reads ″killed.″ Her mentally-ill mother claims to have seen the dead husband. Michael's favorite coffee cup reappears on the table, right where he left it every morning. And when a stranger appears outside Alice's house, she takes a photo of him that seems to change every time she looks at it. Most alarmingly, a gun mysteriously returns to its hiding place under the bed after Alice had gotten rid of it. Alice explores several explanations, including the possibility that she is losing her mind, or that someone is playing practical jokes on her. A therapist whom Alice visits for grief counseling thinks Alice's guilt is what's haunting her, and that she probably has ″some very naughty friends.″ Her friend Kelly reminds her that Steve has a history of pulling pranks and could be engineering all this as a way to drive Alice into his arms, but she finds it difficult to believe anyone could be so cruel. She reluctantly goes with Kelly to visit a psychic who suggests finding a way to force her husband to move on, if indeed he is reaching out to her from the grave. A chance encounter leads Alice to discover that one of her husband's last wishes wasn't fulfilled. She attempts to correct the transgression, hoping this will put to rest any unresolved issues.
However, just as she begins to feel confident about the new man in her life, fresh evidence casts a disturbing and potentially dangerous light on her situation. Alice realizes that she may have been very wrong about who Steve really is. Her mother passes away, a final cryptic warning whispered from her lips. Alice's life turns upside down as her friends and enemies suddenly switch sides, trapping her on a roller coaster of deception and revenge which culminates in one last chance for Alice to right the wrongs and end her nightmare.