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.