With the Gadgetmobile damaged in a high speed chase and considered to be obsolete anyway it's retired from the force and sent to a used car lot where it hangs out with two other former hero sidekick cars from the 50s and 70s. Meanwhile Inspector Gadget (and his replacement Gadgetmobile) is being continually upstaged by new supercop Devon Debonaire and in danger of losing his job if he makes one more blunder. Which he inevitably does but Penny and Brain have suspicions that there's something fishy about Devon and investigate him.
- This film has the same animation style as the Gadgetinis series, paving the way for the concepts to follow in Gadget and the Gadgetinis.
- It should be noted that in this film, Gadget is less bumbling and clueless than his 1983 series counterpart, whereas Penny and Brain get far less screen time.
- Same character designs as "Gadget and the Gadgetinis" but unlike that series Brain and Chief Quimby are still among the supporting cast and Gadget is still an Inspector with the Metro City Police. Just like the live action movie, Gadgetmobile now has a distinctive personality and works as Gadget's partner and the implication is that retroactively it always has.
- Technically, Claw's face is seen in this episode, but since he was using the transformation formula, this doesn't count.
- This turns out not to be the last case, because chronologically the 2015 series and Bigger Caper come afterward: Penny is still 12 years old in "Last Case", 15 years old in the TV series and 16 years old in the film.