Yuji, an author, meets up with his friend Mari looking tired and distraught. He tells her that he has a problem that he cannot tell to anyone else, that there is a person who is alive in his dreams who is trying to break out into the real world. Whenever he falls asleep, the other thing wakes and tries to draw Yuji into its world, so it can take Yuji's place in the real world. He has not slept in three days. Mari seems skeptical and tells Yuji that this story sounds like the type of ficticious story that he would write and asks if he's been to see a doctor. Yuji becomes upset and storms out.
She chases him and says that she was just joking. He replies that he can't go see a doctor, that there would be nothing they could do for him except in the best-case scenerio throw him in the "loony bin". Mari asks what she can do to help, and he asks her to watch over him and make sure he doesn't fall asleep.
Mari tells her parents that she is going on a trip as a cover to help Yuji. But she doesn't believe his story, and thinks that it's just another excuse because he isn't going to make it as a writer. When she arrives at his place, he says that he has just about reached his limit of sleeplessness. Yuji has Mari bind his ankles and wrists together with tape so that the dream person cannot escape. With his limbs bound he finally falls asleep. But as soon as he does Mari sympathetically cuts the tape off and covers him in a blanket. Soonafter she falls asleep herself.
She awakes later to strange scuffling sounds. Yuji's right arm looks as if it has been sucked into his body, and another arm is forcing its way from his mouth, the fingers clawing at the floor to get free. Mari screams for Yuji to wake up as the arm grabs her ankle. He wakes up just in time to catch the arm from his mouth with his own left arm, and faceplants the floor to force it back into his body. He then begins pulling his missing right arm back into its place. Mari helps him fix his inverted fingers, and scolds her for taking off the tape.
Mari grudgingly has to believe him, having seen it for herself. If the dream man escapes, his entire body will be turned inside out. When Mari asks about bones and intestines and what happens to those if he gets turned inside out, Yuji says that his explanation is that he was born with an empty body, or went hollow when his family died. He muses over some of his past dreams and how weirdly real they are. When he was a boy he wanted to fly and tried everything, even taping feathers to his arms. But when he was dreaming, his dream self would laugh at him for trying something so stupid. His dreams were more real than his reality. Mari says that anything is possible in dreams, so why should the dream person want to leave them?
They continue to try and stop it from happening. The tape does not stop it, and evenwhen they clamp his mouth shut it is wrenched back open. Yuji eventually gives up, not wanting to put Mari through any more trouble. He says the reason that the dream person is so stubborn is because he wants Mari, and that Yuji feels the same about her. After confessing this he falls asleep. Mari doesn't want to let him go, and tapes her own arm to Yuji's believing that she can act as an anchor for him. But when his arm starts to get sucked into his body, it takes her arm with it. Two arms emerge from Yuji's mouth as they try to escape. Instead of fighting, Mari decides that she wants to go with Yuji.
Some time later the landlord of Yuji's complex drops by with some police who want to ask him questions. A human figure sits against the wall and invites them in. The police ask about Mari saying that she has disappeared, and notice her tote bag on the floor of his apartment. Yuji says that there is no use looking for her, that she has become his intestine. When the police ask if he has eaten her, the shadowed figure says that he gave her a one way trip to his dream world.