Henry is listening to a tape marked "Exhalation #10" sent to him by his best friend and cop, Paul. Henry has borderline super hearing and is a film maker. When he starts the tape, he hears a woman who has been chained to a wall, struggling to breathe. The recording goes on for almost an hour until she dies. Henry recalls a person can remain alive without food and water for 10 days.

He calls Paul, frustrated and disturbed. Paul apologizes but says he is desperate for anything that might help him uncover where the woman's body is or who killed her. Henry listens for sounds of Paul's wife, Maddy, who knows that Henry is in love with Paul. Paul asks if Henry is still working on the movie that they were once working on together, before Paul's dad died. Henry says he is and hangs up.

When Henry is thirteen years old, he wakes up to some terrible, screaming sound that he compares to a cicada in pain. He discovers he can hear things other people can't. His older brother, Lionel, finds this amusing, and one day when they're in the park, Henry hears the horrible sound again and discovers a girl trapped in a hole in the ground.

Henry keeps listening to the tape until finally he hears the faint sound of a train in the background. He calls Paul to share the clue and says he wants to go with him when he settles on a place to start looking. Henry rewatches clips from the movie he and Paul were making in college but this time there are jagged trees interspersed in the shots from a low angle that they never filmed.

Paul and Henry drive around the railroad crossings closest to the site of the abandoned car crash where the tape was first discovered until Henry hears the horrible sound again. He tells Paul to turn into an unmarked road, and when they get out of the car, Henry sees the same trees that appeared in his film, but in the film, it was from a lower angle, like a child's perspective.

They find a shack that has a tape labeled "Exsanguination" and a mallet. They watch the tape on Henry's camcorder. In it, a man wearing a ski mask brutalizes a little girl and leaves her to bleed out. Paul apologizes for dragging Henry into this, but Henry sees he is just guilty not regretful. Henry knows Paul couldn't share this case with Mandy because sharing the burden of deaths like this severs a relationship. Henry would do it all over again too because he can't say no to Paul. On the drive back, Paul says he hopes Henry finds someone and he's sorry that person couldn't be him.

Henry watches his and Paul's half-finished movie and finds more corrupted shots. He and Paul agree to go looking again, this time for a house with a barn that Henry saw in the movie.

They follow Henry's hearing until it leads them to the house, where they find a man's rotting body on a bed. In the basement, they discover where the woman from Exhalation #10 died with the camera tripod still pointing at the spot. The woman etched the words "Find Me" into the floorboards. They find more tapes labeled Exhalation 1-9, Contusion, Asphyxiation, and Delirium. Each method of dying is a new victim, and they find the bodies of each one in the land around the house, but never find the woman's body.

When Henry watches his and Paul's movie again, the frames are all normal.

Henry moves to Los Angeles and starts working on a new film. He meets a photography director and gets married. He and Paul lose touch. Though he could never find the woman or her killer, he makes a movie imagining what her life was like that wins him an Oscar. He is happier than ever, but he still thinks about the movie he never finished with Paul. He knows he will always help Paul if Paul ever asks again and that Paul will always hold a place in his heart.