Scooby-Doo! Mystery Incorporated

'Scooby-Doo! Mystery Incorporated' is an animated television series based on the classic Scooby-Doo series, and it occasionally features characters and references from the Jonny Quest series.

Crossover characters
These original Jonny Quest characters appear:
 * Dr. Benton Quest
 * Race Bannon
 * Jonny Quest
 * Hadji
 * Bandit
 * Dr. Zin

Notable related characters:
 * Radley Crown / Blue Falcon, a security guard at Quest Research Laboratories who's modified by Dr. Quest to be a superhero
 * Reggie / Dynomutt, a security dog who's modified by Dr. Quest to be a superhero
 * Jenny Zin, Dr. Zin's daughter

Additional prominent characters:
 * Scooby-Doo
 * Shaggy
 * Velma
 * Daphne
 * Fred

Pawn of Shadows
After the Scooby gang apprehends Alice / Obliteratrix, she mentions getting equipment from Quest Research Laboratories, which was a shell corporation of Destroido. During her explanation, she's shown in a flashback sneaking into Quest Research Laboratories while Dr. Quest, Jonny, Hadji, and Race laugh watching Bandit jump up to try to catch a toy airplane.

Heart of Evil
The episode is a crossover of both the Jonny Quest series and the 1970's Dynomutt, Dog Wonder series.

Teaser
Five years earlier, at Quest Research Laboratories. Security guard Radley Crown and his security dog Reggie are on patrol when there's an explosion, and they run to investigate. A mechanical dragon has busted through the walls into Quest Research Labs. Radley fires his gun at the mechanical dragon, which picks up Radley. Reggie jumps on the robots back, biting it, and causing an electrical surge. The robot drops Radley.

Race Bannon arrives and uses a bazooka to shook the robot, sending it back out of the building. Dr. Quest joins him, saying, "Good shot, Race." They go to the whole in the wall, but the robot has left. Dr. Quest thinks they haven't seen the last of it.

Radley hold Reggie, who's hurt from attacking the mechanical dragon, and he asks them to help him. Dr. Quest thinks of Bandit, and agrees. He asks Race to "ready the Quest Lab."

Act 1
In the present day, Blue Falcon and Dynomutt are superheroes who cross paths with the Scooby Gang. Dynomutt in particular has various abilities and cybernetic parts. The mechanical dragon, like the one that attacked Quest Research Labs five years earlier, attacks City Hall's records room, and Blue Falcon and Dynomutt have been tracking it in hopes of getting to its master. The mechanical dragon gets away. Dynomutt likes the kids and says they should work together.

Velma later does research on what the mechanical dragon was looking for, and it was going through old sales records of Crystal Cove businesses. Velma finds one file in particular on Quest Industries: "It was a cutting edge tech firm until it was sold to Crystal Cove's most prominent corporation: Destroido."

The team goes to Destroido Corp. building, and the mechanical dragon attacks the lab and appears to be uploading data. A voice speaks to the dragon, saying, "Take heart, my precious dragon. Fate has put our long-sought prize in our clutches." The dragon robot collapses. Blue Falcon recognizes the voice as being from Dr. Zin.

From a remote control room, Dr. Zin muses that Blue Falcon has discovered he's behind the mechanical dragons. Zin is after the "Quest X Power Source" and he has discovered it's location: inside Dynomutt. He commands the mechanical dragon to "get Blue Falcon and that mutt", so the dragon grabs Blue Falcon and Scooby-Doo and flies away.

Act 2
Blue Falcon wakes up at Volcano Island, where he and Scooby-Doo are tied up. Dr. Zin threatens to hurt Scooby-Doo if Blue Falcon doesn't tell him how to extract the Quest X Power Source. Blue Falcon refuses to talk, because Dr. Zin grabbed the wrong dog.

Back at Destroido, Shaggy grabs Destroido's owner Mr. E to get information out of him. Mr. E tells them that when he "bought Quest Industries, there was an asset listed as the Quest X Power Source, but [he] was never able to locate it." Dynomutt can track Blue Falcon's location and he can get them to Volcano Island in the Falcon Car, and they take off.

At Volcano Island, Dr. Zin has Scooby-Doo x-rayed and confirms that he doesn't hold the Quest X Power Source. The mechanical dragon goes to move them to the "cells of despair" but collapses. Dr. Zin rushes to its side, telling it, "Be strong, my dragon." Alarms go off as the Scooby Gang approaches in the flying Falcon Car, and Zin orders that they be shot down and for his team to look for the dog's remains. Zin assures his dragon that it will "soon have enough power for a lifetime." The Scooby Gang arrive, having survived the crash by falling into the water before the flying car was shot down.

They defeat Zin's henchmen, and Zin laments that he has failed his dragon, and he tells Dynomutt it's his fault. Dynomutt doesn't understand, so Blue Falcon explains, finally telling Dynomutt the truth: Five years earlier, Dr. Quest "was able to replace most of Reggie's damaged body parts with robotic replacements." He chooses to power the dog "with the most powerful generator on the planet", the Quest X Power Source.

Velma has realized that the event five years earlier also affected Zin's mechanical dragon, which actually holds a human being. Zin tells them that it's his own daughter Jenny in the dragon battle suit, and the accident at Quest Research Labs caused the suit to fuse to her and has been feeding off her life force ever since. He needs the Quest X Power Source for Jenny to survive. Dynomutt says that he's "never too busy to help a fellow cyborg with a jump start", and shares his power with the dragon suit. It's enough power to free Jenny from the suit, and she collapses on the ground. Zin runs to her and cries with happiness.

Zin gives his thanks to them all, then says they must all be destroyed in the volcanic eruption as he and Jenny escape with rocket packs.

The Scooby Gang escapes when Dynomutt turns into a floating motorboat and they get away before the island volcano erupts. Blue Falcon vows to find Zin.

Notes / trivia

 * Blue Falcon and Dynomutt also appear in Harvey Birdman, Attorney at Law; Harvey's apparent murder of Dynomutt leads into an episode which features the Lizard Men from the Jonny Quest series, so it's another crossover episode that features both series.