Shogo Sano (Kuranosuke Sasaki) of the Metropolitan Police Department's First Investigation Division is a detective who will stop at nothing to solve a case. One day, the body of a neurosurgeon is discovered in an underground parking lot; the victim has died under bizarre circumstances, with four knives driven into his throat. Sano launches an investigation alongside his partner, Anna Hazumi (Yuri Tsunematsu), and Toru Kanzaki (Taishi Nakagawa), a researcher seconded from the National Research Institute of Police Science. However, the situation takes a dramatic turn when a second victim is found. As they trace the victim's background and clues from the crime scene, the existence of a mysterious research facility emerges as a key lead in the investigation.
Sano's ex-wife, Kaoru (Maki Sakai), emerged as a suspect. Sano was left speechless when confronted with dashcam footage capturing the disposal of the body. Kaoru subsequently committed suicide, leading to the disbanding of the investigation headquarters due to the suspect's death. Having had no contact with Kaoru since she asked for a divorce three years prior, Sano believed in her innocence and resolved to continue the investigation to uncover the truth. Meanwhile, Kanzaki and Anna arrived at a research facility known as "ALIUS Lab," but...
Just as Kanzaki arrives at an unexpected hypothesis regarding "ALIUS," a third murder occurs. The victim is the president of an investment fund, found with two knives driven into his throat. The suspect claims to have no memory of the crime. Meanwhile, Sano grows increasingly suspicious due to unnatural, inaccurate media reports and the baffling maneuvers of high-ranking police officials. Sano and Kanzaki head to the research facility that links all three victims, but... A video file obtained by Sano ultimately provides the breakthrough needed to move the stalled investigation forward.
It is revealed that Anna, who had been working alongside them, is actually an undercover agent for Public Security. Confronted by Sano, she discloses her true objective—a revelation that exposes the shocking reality of the police investigation surrounding "ALIUS," far exceeding anything they had imagined. Sano and Kanzaki are left speechless by the news. Yet, the identity of the serial killer and their true motives remain a mystery. Encouraged by Kanzaki's words, Sano resolves once more to uncover the truth behind the case.
A shocking truth came to light—one that even Kanzaki himself had not known. Yet, Sano resolved to trust Kanzaki and continue working alongside him; following a message left by Kaoru, the two headed to a specific facility. There, testimonies from Mamiya (Takashi Yamanaka) and Ashida (Osamu Kao) revealed the true purpose of "ALIUS LAB" and the reason Kaoru had left Sano. Eventually, Sano and Kanzaki closed in on the culprit's identity—but the killer's gun was already aimed at their target from behind.
The true culprit of the serial murders, Souma Sakaki (Kenta Inozuka), aims to assassinate Kaburagi (Hiroshi Okochi), the ringleader of Project Marionette, which plans to use ALIUS for military purposes. In order to prevent the final murder, Sano and Kanzaki rush to Kaburagi's lecture venue, where they finally confront Sakaki, who aims his gun at him for revenge. What is told there is the sad past of Sakaki, who was at the mercy of the nation's grand ambitions. In order to inherit the feelings of his late wife Kaoru and stop the chain of tragedies, Sano desperately tries to persuade him, but...
