‘Signal The Movie Cold Case Investigation Unit’: Obvious but with plenty of panache

Quite a few Japanese films serve as an extra episode of a popular TV series. They even get their own abbreviation: “SP” (special program).

Those who venture into these SPs unacquainted with the world of the TV show can feel as though they’ve crashed a family dinner. Fortunately, “Signal The Movie Cold Case Investigation Unit,” a cop actioner that is the film offshoot of a 2018 Fuji TV series that was itself based on a 2016 Korean show, provides a rapid-fire digest in the opening minutes to get the uninitiated up to speed.

But an investment in the characters is still assumed, which is not surprising for a film targeted at core “Signal” fans. The personalities of the main cast, which range from the spit-flecked emotional (Kazuki Kitamura) to the clenched-jaw stoic (Michiko Kichise), are carryovers from the show, though director Hajime Hashimoto, a veteran of the long-running “Aibou: Tokyo Detective Duo” TV and film series, is new to the “Signal” team.

“Signal” departs from the typical cop genre plot in that two members of its title cold case unit, detective Kento Saegusa (Kentaro Sakaguchi) and his superior, Misaki Sakurai (Kichise), communicate with a cop from 2009, Takeshi Oyama (Kitamura), via battery-less walkie-talkies that miraculously, if erratically, connect across the years.

This gimmick is not new or rare — Hideyuki Hirayama’s 2001 “Turn” did something similar, as did Aya Igashi’s “No Call No Life,” which opened just last month. In “Signal,” however, the time-traveling device serves to both raise the tension and add a note of poignance: Takeshi, we soon learn, is no longer among the living in the present of 2021 and is unaware of his impending doom. Saving him by changing the past, however, is not an immediate priority of the other two cops.

The plot is dense but boils down to collusion at the top of the police and government power structure to cover up the truth about a series of untimely deaths. Then, someone privy to the facts and grieving for one of the victims sets out on a mission of revenge.

Untangling this knot of conspiracy and crime becomes the work of Kento once he notices similarities between the suspicious death of a high-ranked state security bureaucrat in the present and the supposedly accidental deaths of two other elite officials back in 2009. The connecting thread: a fictional deadly gas, “heron,” used in a 2001 terrorist incident and assumed to have been destroyed. Did one of the terrorists escape with a supply of heron? Perhaps Takeshi can help.

The ensuing action is staged with panache and impact — kudos to action director Nobuhiko Tanaka as well as to Sakaguchi as Kento, who brings a sweaty commitment to his fight scenes. Like many other local action heroes, though, Kento is laughably indestructible, battling on even after losing enough blood to supply an emergency room.

Also, the climax is packed with positive messaging that is thuddingly obvious. Yes, we can change the future if we try but what, I wondered, about poor Takeshi, seemingly hung out to dry? The film does give us an answer to his dilemma, as well as a pointed, if general, critique of this country’s powerful and mighty, insulated from the masses they rule by their arrogance and sense of entitlement.

Solving that particular problem, however, is beyond even the abilities of time-jumping cops.

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