, also known as , is a Japanese police procedural television series starring Kentaro Sakaguchi, Michiko Kichise and Kazuki Kitamura. It is a remake of the South Korean drama of the same name written by Kim Eun-hee and aired every Tuesday at 21:00 JST from April 10 to June 12, 2018, on Fuji TV.
A sequel film, Signal the Movie, was released in theaters in Japan on April 2, 2021.
Boy group BTS from South Korea sang the opening theme song of the series entitled "Don't Leave Me".
A sequel film, simply titled Signal the Movie, was released in Japan on April 2, 2021. The film was directed by , co-written by KÃ Âsuke Nishi and Hiroshi Hayashi, and distributed by Toho, with cast members from the television series reprising their respective roles.