The Millionaire Detective - Balance: UNLIMITED

Haru Kato, a detective working for the Modern Crime Prevention Task Force in the Metropolitan Police Department, has been ordered to work on security at the Classic Car Festival being held in Ginza. At the event, he runs into his former colleagues from the First Investigation Division, who were called in because of a bomb threat. As the time until the bomb is set to explode quickly approaches, he suggests that they should cancel the festival but no one listens to him. In this tense situation, Daisuke Kambe, who claims to be the newly appointed inspector, arrives on the scene.

Daisuke and Kato are ordered by their boss to become partners. They find a pair of comedians performing on the street and suspect that they are involved with drugs. They contact the Metropolitan Police Department about the comedians, but it becomes apparent that Kato and Daisuke have completely different approaches to solving crimes. The kindhearted Kato is disgusted by how Daisuke relies on his wealth to solve problems. They both go their separate ways in the investigation. Kato asks a journalist who he is friends with to help him gather information. While they are on a stakeout, they meet a mysterious woman.

Moments after Kato returns from his business trip and steps out of the bullet train, a hostage crisis occurs on the same train. The suspect has taken hostages and, for some reason, begins live streaming his actions on the internet. While the First Investigation Division and Special Forces arrive on the scene, Kato discovers that the suspect is the same young man that was sitting next to him in the train. The First Investigation Division decide that they have no choice but to shoot the suspect, but Kato tries to talk them out of it. However, due to an incident caused by Kato in the past, his pleas fall on deaf ears.

On his day off, a family situation leads Daisuke to break out of his own mansion. Shortly after he steps out, Kato calls him to help a young boy who is distraught over a lost dog. Daisuke realizes that he left his wallet and gadgets back at the mansion. Unable to resort to his usual tactics, they have difficulty finding the lost dog. Daisuke doesn't want to go home, so Kato reluctantly invites him into his apartment.

The president from the Republic of Poliador arrives in Japan, and the Modern Crime Prevention Task Force are assigned to protect the embassy. After a body is found inside the building, the president and Daisuke are forced to the panic room.

Kato takes the heat for the handling of the embassy case. Daisuke checks out the device left behind by the suspect, but for some reason his AI butler, HEUSC, refuses to listen to his commands. Cho-san also investigates articles left behind at the crime scene and pursues the case from a different angle with the help of Kato. Their investigation leads them to a woman named Imura who works at a manufacturing company. However, Daisuke's actions interfere with their meeting with the woman.