A brilliant, wheelchair-bound scientist invents a form of exo-skeleton called the Mechanically Augmented Neuro Transmitter Interception System (M.A.N.T.I.S.) that turns him into a superhero and gives him the ability to fight the crime wave that is engulfing his city.

Charlie and Rhonda are a sweet and comfortable married couple on vacation with their lovely daughter Daphne. They find a rundown boarding house and its haggard owner, Joseph, an ex-con whose mother has just died and left him the property. He doesn't know why this cheerful couple would want to vacation in the worst part of Los Angeles, but he doesn't know they're visitors from outer space, and their idea of fun is murdering and eating humanity's worst.

Weird things are happening in the town of Justice, Arizona: three sheriffs have disappeared, and someone is killing the rancher's livestock in a bizarre, ritualistic fashion. Locals believe the incidents were caused by aliens...
But a visiting couple, Charlie and Rhonda, knows better – because they're aliens themselves. When no one else will, Charlie and Rhonda volunteer to be the new sheriffs to get to bottom of the crimes. Hiding behind the power of the badge, the two make their own rules, punishing wrong-doers with their own form of "eye-for-an-eye" alien vengeance.
Follow this twisted, outer space "Bonnie and Clyde" as they attempt to bring Justice the justice it deserves.

In the original movie, the cyborg-teachers were all destroyed. Well that's what we thought, but there's one more rogue military robot out there determined to clean up the education system.