Right now you can watch Signal in the US on Rakuten Viki — and it earns its twists rather than manufacturing them. The show says what it needs to say in a single season, no filler. Its 7/10 TMDB score, built from 14 ratings, reflects a title that consistently delivers. Kentaro Sakaguchi sets the tone, and the ensemble matches it scene for scene. Start it on Rakuten Viki whenever you need something guaranteed to land.

Signal is not trying to be everything to everyone, and that focus is exactly what makes it work. Signal treats its mystery as a means, not an end in itself. Two detectives communicate through a walkie-talkie to solve a cold case. One detective exists in the present day, and the other detective exists 15 years in the past. Kentaro Sakaguchi and Kazuki Kitamura lead a cast that never lets the mystery feel thin. It first aired in 2018. Signal is at its best in the quiet scenes between the plot beats, where the character work actually happens. It knows exactly what it is, and does not try to be anything else.

If you cannot walk away from a good mystery, Signal will keep you hooked. Viewers who responded to Unforgettable will find a lot to like here too. Best experienced as a single, sustained watch if your schedule allows. Kentaro Sakaguchi anchors it, but the writing does the real work. If you are going to commit to one crime drama this month, make it this one.

Signal wrapped up in 2018 — and 1 season is available to watch from start to finish. Find exactly where it's streaming below, and TV Butler Pro's free voice app makes it effortless to track your progress as you go. Just say the name, and Butler finds it instantly, tells you which service has it, and remembers exactly where you left off.