Trepanation is the procedure of drilling holes in a person's head, supposedly increasing the circulation of blood and helping to improve the pressure inside one's skull, bringing out a person's sixth sense and causing them to gain superhuman powers such as ESP, being able to see ghosts, and controlling objects remotely with one's mind. This is speculative fiction based on the concept of trepanation.
Susumu Nakoshi is a 34-year-old homeless man living out of his car. For two weeks, he has declined his fellow homeless men's invitations to set up a tent with them, preferring to sleep in his car. However, one day, he is accosted by a strange-looking man searching for participants to subject themselves to trepanation. Nakoshi tells the man to leave, and discards the flier he'd placed on his windshield. However, when his car is towed, he agrees to let medical student Manabu Itoh drill a hole in his skull in exchange for 700,000 yen. Itoh claims to be interested in trepanation for the sake of science; he is interested in humans, fascinated with ESP and the sixth sense, and wants to disprove the existence of the occult. Itoh's father owns a lab facility, as his father is a rich hospital director. Itoh performs the trepanation surgery on Nakoshi and does a variety of ESP tests. When Nakoshi reveals that he sees distorted humans when using only the left side of his body, Itoh researches and discovers that Nakoshi can see homunculi.