Eighteen-year-old Kei Watanabe has lived his whole life seeing what others cannot: the bonds between people appear to him as colored threads—red for love, black for hatred, gold for financial ties, and countless other shades that reveal hidden emotions, lies, and intentions. This unwanted ability has burdened him since childhood, forcing him to witness every betrayal and deception around him. Unable to trust anyone, Kei withdrew from society and became a recluse, spending his days in his room ordering food online and avoiding human contact.

His isolation ends the day he is stopped for a field interview by police officer Zen Mutou and his younger sister Kanade. Zen, a charismatic and seemingly reckless man, immediately recognizes Kei’s ability. Zen himself possesses a different Psycho Eye—the power to see other people’s vigilance as a visible membrane, allowing him to read their next moves and counter any attack with near-perfect precision. Kanade, too, has her own variant: she can perceive routes and pathways, making her an expert tracker and navigator. Zen forces Kei to help with an urgent case: a user named “Urs” has posted a crime threat online. Using his ability to see the threads on a video call, Kei locates Urs—a lonely girl with no bonds to anyone—and talks her down, saving her life. This success convinces Kei to join Zen’s secret unit, the Special Surveillance Unit (nicknamed “Marume”), an elite police squad composed entirely of Psycho Eye users.

Marume operates from a hidden base, tasked with solving cases that normal police cannot handle. Kei meets the other members: Bon, a former con artist who can read the memories left on objects and rewind time to see past events; and Tama Amou, whose ability lets her see the “credibility” of a person’s words as a monetary amount and force them to tell the truth through questioning. The team trains and lives together, and Kei slowly learns to trust again. But the organization they face, the criminal syndicate “World’s Eye,” is ruthless. World’s Eye kidnaps Psycho Eye users to harvest their eyes and transplant them into others, creating artificial ability wielders for their own ends. They have operatives with terrifying powers, such as the twin assassins Jin and Siana. Jin can manipulate causality to cause fatal “accidents” (the “Butterfly Effect” ability), while Siana uses clairvoyance and precognition to support him.

The story deepens when Kei’s long-missing father, Akira Watanabe, suddenly reappears. Akira claims he abandoned the family to protect Kei from debt collectors, and Kei, desperate for a family bond, believes him. But it is all a calculated manipulation: Akira is actually the true leader of World’s Eye. He orchestrated his return to drag Kei into despair and recruit him for the organization. In a devastating confrontation at a movie theater, Akira shoots Zen—who steps in to shield Kei—and leaves the injured mentor for dead. Zen’s fall shatters Marume. The police internal affairs officer, Onigawa, who has always resented the unit, takes over as interim commander and threatens to disband them.

In his grief, Kei is kidnapped by a mysterious man named Ishikawa Goman, who has his own agenda. Goman uses Kei’s ability to further his plans, but the situation escalates when a third faction, the assassination group Corpes Corp., enters the battlefield. A three-way firefight erupts between Marume (now fighting under Onigawa’s reluctant leadership), Goman’s forces, and Corpes Corp. With the ghost-like guidance of Zen’s spirit—whom Urs can now see and communicate with—Kei manages to destroy Corpes Corp.’s strike team and capture Goman. He returns to Marume, but the unit remains fractured, the traitor still unidentified, and his father still at large.

Throughout the narrative, Kei’s ability evolves. He learns to read the thickness, color, and movement of threads to perceive not just relationships but also the location of hidden enemies, the emotions behind online messages, and even the visual ghosts of people in video footage. The series blends psychological suspense, intense hand-to-hand and ability-based combat, and a coming-of-age story about a lonely young man who discovers that his curse can be a weapon, and that bonds—even painful ones—are worth protecting.