This isn't the Patlabor you know. It abandons the ensemble cop procedural entirely, trades it for a noir detective mystery where two exhausted men hunt a biological weapon through Tokyo Bay, and somehow that decision works. The animation is so detailed it makes you feel the weight of every failed lead and dead end. By the end, when the mystery collapses into something personal and devastating, you realize the movie spent its entire runtime preparing you to care about one man's guilt in ways the franchise never attempted before.

When accidents involving Labors begin to climb around Tokyo Bay, police detectives Kusumi and Hata are put on the case. Their investigation turns up a chain of government cover-ups and a conspiracy surrounding a new biological weapon called WXIII, or Wasted Thirteen, along with a tragic personal link to Hata. Stopping the threat means working with the military and drawing WXIII into a final clash with the Labors of Special Vehicle Division 2. The film is a mecha science fiction side story set between the first and second Patlabor movies.