Chapter 12

Hole in Chest (胸の穴, Mune no Ana) is the 12th chapter of the Parasyte manga series, written and illustrated by Hitoshi Iwaaki.

Overview
''After waking up from a nightmare and coming to the realization that his mother may be dead, Shinichi is confronted by a parasite. The parasite has control of his mother's body, and unable to accept what's before him, Shinichi is stabbed through the heart. After Migi heals Shinichi, he learns that his father is in a hospital. Affirming his resolve to kill the parasites, he heads off to his father.''

Summary
Shinichi dreams of a past conversation with his parents about their vacation, then of his father's pained words during the call home. He awakens to the morning sun and stays home, awaiting another call from his father. Remembering that the perpetrator was called a "monster", Shinichi begins to blame Migi for its species having attacked his parents.

Migi warns him that a parasite is approaching and gets ready for battle, expecting it to attack them once it realizes what they are. Shinichi barely pays attention, blaming Migi for convincing him that they would be fine on vacation, to which Migi replies that it had simply said it would be safer percentagewise. Angered, Shinichi says that he should have cut it off at the start, and that he should have told his mother. Migi interrupts him because of the fight coming up, which prompts Shinichi to grab a knife. Migi tells him he won't need it because Migi will attack before it realizes they're enemies, but Shinichi wants the knife anyway because of the hate he feels for the parasites.

The intruding parasite stops in front of the house, then unlocks the door, which makes Shinichi realize it had a key. It enters, wearing Nobuko's face, and figures out that "that man", Kazuyuki, isn't home. It also realizes that Migi is in Shinichi's hand instead of in the brain. Unwilling to believe that his mother is dead, Shinichi calls the parasite "mom" and places a knife in front of Migi, preventing it from attacking the parasite. Migi tries to tell him that it's not his mother and it stole his mother's head.

The parasite turns away slightly, wondering if Kazuyuki is dead, then decides it should return to double check. Still in denial, Shinichi speaks as if he were telling his mother everything about Migi, interrupting when Migi once again tries to tell him his mother is dead and slicing the knife into his own arm. Shinichi asks the parasite impersonating his mother about the burn and tells it that he's never apologized. The parasite unfurls its head and stabs Shinichi in the heart. He collapses.

As the parasite leaves it tells Migi that its failure to take Shinichi's head cost it its life.

Realizing that it can't heal a heart in the few minutes before it dies, Migi decides to seal the wound and replace Shinichi's heart for as long as it takes to heal him. Shinichi coughs, but doesn't reawaken, and Migi manually repairs the wound by gathering cells from the rest of Shinichi's body to fix and reinforce it, slowly moving back to Shinichi's arm in the process.

The next day, Satomi is seen pondering on Shinichi's multiple-day absence.

During the healing, Migi feeds Shinichi a mix of sugar and water, and he awakens three days later as his house phone rings. He manages to stumble to the bathroom and looks at the scar massive over his chest, wondering if Migi patched him up. He then slides to the floor, realizing that the past events weren't a bad dream.

The phone rings again and he picks it up. A nurse from the hospital his father is in is calling, and tells him that Kazuyuki is in no danger of dying as well as requests he bring a change of clothes whenever he comes to visit. Remembering that the parasite had stated its intention to go back and kill Kazuyuki, Shinichi hurries to pack and head out. He meets Satomi on the doorstep of his house.

Satomi came to check up on him because she was afraid he was sick alone at home. He tells her his father was injured and she says his mother must be all alone, making him react with emotional pain. He tells her he won't be at school for awhile and walks away. Satomi asks if he'll come back. He smiles, but doesn't answer.