A time limit suspense where criminals solve the case with a voice as a clue, set in an ECU (Emergency Call Unit) newly established in the emergency command room of the Koto station. Higuchi (Toshiaki Karasawa), who was once said to be a supreme detective, rescues people who seek help in cooperation with voiceprint analysts. Yoko Maki plays the voiceprint analyst, Hikari, as the director of the emergency command office.