Do you remember the classic 80s cartoon "Adventures of the Gummi Bears"? It was about a group of anthropomorphic bears who lived in a hidden kingdom and used a magical juice to bounce around and fight evil. Well, what if I told you that there was a secret crossover episode with another 80s icon, Danger Mouse?
That's right, the world's greatest secret agent and his faithful sidekick Penfold somehow end up in Gummi Glen, where they meet the friendly bears and joined them in their adventures. How did they get there? What was their mission? And how did they get along with the Gummis?
The episode begins with Danger Mouse and Penfold in their flying car, the MKIII, chasing after their arch-nemesis Baron Greenback, who has stolen a mysterious device from a top-secret laboratory. The device is a portal generator, which can open wormholes to different dimensions. Greenback plans to use it to escape from Danger Mouse and conquer other worlds.
However, as they are flying over a forest, the device malfunctions and creates a huge portal in the sky, sucking in both the villains and the heroes. Danger Mouse and Penfold manage to eject from the MKIII before it crashes, but they lose sight of Greenback and his henchmen. They find themselves in a strange land, full of trees, flowers and animals. They also wonder where they are and how they can get back.
Meanwhile, the Gummis are having their usual problems with Duke Igthorn, the evil lord who wants to capture them and steal their secrets. He has sent his ogres to raid Gummi Glen, hoping to find some Gummiberry juice or some ancient Gummi artefacts. The Gummis are alerted by their lookout Tummi, who sees the ogres approaching. They quickly prepare to defend their home, using their traps, weapons and juice.
After fighting off the ogres, they hear a loud explosion nearby. They think it might be another of Igthorn's tricks, so they send Sunni, Cubbi and Gruffi to investigate. They find the wreckage of the MKIII, but no sign of its occupants. They are puzzled by the strange vehicle, which looks like nothing they have ever seen before. They decide to take it back to Gummi Glen.
At the same time, Danger Mouse and Penfold are wandering around the forest, looking for clues. They encounter some of the local wildlife, such as squirrels, rabbits and birds, but none of them can help them. They also run into some trouble with a hungry wolf, a grumpy bear and a swarm of bees, but they manage to escape using their wits and gadgets.
They eventually stumble upon Gummi Glen, where they are greeted by Sunni, Cubbi, Gruffi, Zummi, Grammi and Gusto. The Gummis are surprised to see two strange creatures wearing clothes and talking. They think they might be spies sent by Igthorn or Greenback, so they are wary of them. However, they soon realize that they are not enemies, but friends who need their help.
They invite them inside their home, where they introduce themselves and explain their situation. The Gummis are amazed by their story and offer to help them find Greenback and the portal device. They also show them the MK III, which they have brought to their workshop. Danger Mouse is relieved to see that it is not completely destroyed and that he can fix it with some spare parts, along with help from Gruffi.
Danger Mouse and Penfold are impressed by the Gummis' knowledge and skills. They also enjoy their company and have fun with them. They bond with the Gummi's, who are curious about their lives and adventures. Sunni, though, develops a crush on Danger Mouse, who she finds brave, charismatic and handsome. She tries to impress him with her skills and charm, although Danger Mouse is oblivious to her feelings.
The Gummis also share some of their history and culture with Danger Mouse and Penfold. They tell them about the Great Gummis, who left long ago to find a new home after being persecuted by humans. They show them some of their inventions and discoveries, such as the Gummi Medallion, which can activate hidden Gummi devices around the world. They also allow them to try some Gummiberry juice, which allows them to bounce like the Gummis. However, Penfold cannot control his bouncing, and finds that it also gives him terrible wind.
However, Igthorn is still plotting to capture the Gummis and take over the kingdom. He learns from one of his spies that there are two new visitors in Gummi Glen who might have something to do with the explosion he heard earlier. He suspects that they might have some powerful weapon or secret that he can use against King Gregor.
He decides to launch a full-scale attack on Gummi Glen with his army of ogres. He also hires some mercenaries to help him: Greenback and his henchman Stiletto. Greenback has survived the portal and has landed in Igthorn's castle. He has agreed to work with Igthorn in exchange for his help to find the portal device and return to his own dimension.
The Gummis are caught off guard by the sudden assault. They try to fight back, but they are outnumbered and outmatched. They are forced to retreat to their underground tunnels, where they hope to hold off the invaders. Danger Mouse and Penfold join them in the defense, using their gadgets and skills.
However, they soon realize that they can't win by hiding. They need to take the fight to the enemy and stop them from destroying Gummi Glen. They also need to find Greenback and the portal device before it's too late. They decide to split up into two teams: one team will stay behind and protect Gummi Glen, while the other team will sneak into Igthorn's castle and confront Greenback.
The team that stays behind consists of Zummi, Grammi, Gusto, Tummi and Gruffi. They use their traps, weapons and juice to fend off the ogres and mercenaries. They also use their Gummi Medallion to activate some of the hidden Gummi devices around Gummi Glen, such as a giant catapult, a water cannon and a firework launcher. They manage to hold their ground and cause some damage to the enemy.
The team that sneaks into Igthorn's castle consists of Danger Mouse, Penfold, Sunni and Cubbi. They use their stealth and cunning to infiltrate the castle without being noticed. They encounter some guards and traps along the way, but they overcome them with ease. They eventually reach the throne room, where they find Greenback holding the portal device.
Greenback is surprised to see Danger Mouse and Penfold again. He taunts them and tells them that he has already used the device to open a portal to another dimension, where he plans to escape with Igthorn's treasure. He also reveals that he has rigged the device to explode after he leaves, which will destroy the castle and everything around it.
Danger Mouse and Penfold are shocked by Greenback's plan. They try to stop him, but they are attacked by Igthorn, who has arrived with some of his ogres. A fierce battle ensues between the two sides. Danger Mouse and Penfold fight against Greenback and his henchmen, while Sunni and Cubbi fight against Igthorn and his ogres.
The fight is intense and chaotic. Danger Mouse manages to knock out Stiletto and Leatherhead with his karate skills. Penfold uses his gadgets to distract and disable some of the ogres with smoke bombs, glue guns and rubber ducks. Sunni uses her bow and arrows to shoot at Igthorn from a distance. Cubbi uses his wooden sword to slash at some of the ogres up close.
However, they are still outnumbered and outgunned. Greenback manages to activate the portal device and throws it into the air. He grabs a bag of gold coins and jumps into the portal. He laughs maniacally as he disappears into another dimension.
Danger Mouse sees the portal device in the air and realizes that it is about to explode. He quickly grabs Penfold and runs towards it. He jumps into the air and catches the device before it detonates. He then throws it back into the portal, hoping that it will explode on Greenback's side.
However, as he does so, he accidentally falls into the portal himself. Sunni sees this and screams in horror. She runs towards the portal, and manages to grab Danger Mouse's hand just in the nick of time. She pulls them back into their world, saving him from certain doom. The portal explodes on Greenback's side, trapping him another dimension.
Sunni hugs Danger Mouse tightly as she brings him back to safety. She tells him that she is glad he is alive. Danger Mouse is stunned by what just happened. He thanks Sunni for saving his life. They escape the castle just before it collapses into rubble, leaving Igthorn furious with rage.
Danger Mouse and Penfold prepare to leave Gummi Glenn, using the readings from the portal to return to their own world and time. Sunni is heartbroken to see Danger Mouse leave, but realises they have to go back to where they belong. Danger Mouse and Penfold then take off in the repaired MKIII, and return home for further adventures.