Signal

Fifteen years after witnessing the kidnapping of a girl at school, Kento hears someone calling his name through a discarded two-way radio.

Kento determines that the true culprit is a nurse named Keiko Yoshimoto, but she refuses to crack under questioning from Misaki.

The two-way radio reconnects after the reinvestigation starts. Just as Kento had suspected, Ooyama had been part of the initial investigation in 1997.

1997. Ooyama learns from Kento that the next victim will be his friend Midori. In 2018, Kento holds his breath for a favorable outcome.

Kento learns that Ooyama went missing 18 years ago and was later dishonorably discharged. In 1998, Ooyama works on a certain serial larceny case.

Fresh out of prison, kudo becomes the prime suspect in Kaori's kidnapping. Ooyama expresses his anguish when Kento contacts him on the two-way radio.

Kento thinks of changing the future by catching the real culprit. He teams up with Ooyama again in 1998 in order to apprehend the criminal.

In 1999, Ooyama investigates an incident that led to a female student's suicide attempt. Kento's brother is later arrested as the main instigator.

Among Ooyama's belongings, Kento finds a business card to the yakitori restaurant he used frequent by himself as a little boy.

After arriving at the conclusion that his brother did not commit suicide, Kento begs Ooyama to change the past in order to save his brother.