There is a thief in Gummi Glen, so Zummi and Grammi team up to find the rat. Unfortunately, Zummi casts the wrong spell which ends up shrinking them to a dimunative size, and they only have a limited amount of time to reverse it.

After an autumn of hard work and preparation for the coming winter, the Gummis are looking forward to the holiday of Fall's Farewell, but Sunni goes overboard with the celebration trying to impress Calla.

Tummi builds a full size boat, which Gruffi wants scuttled. However, out of respect for all the work done, he allows Tummi one sailing trip. This trip takes an unexpected turn when they end up on a volcanic island inhabited only by another Gummi Bear - an artist by the name of Gusto.

Tummi has to clean up a big mess in Gummi Glen and bemoans that he is slow at the job. After tricking a tired Zummi into casting a spell on him, he learns that faster is not always more efficient when the spell proves unpredictable.

Sunni creates a growing potion while Toadie is cast out by Duke Igthorn. The two meet to unexpected results.

Igthorn puts Dunwyn to sleep, leaving only Calla, Cavin, and the Gummi Bears to protect the castle.

Chummi Gummi comes to Gummi Glen in search of the Great Gummis. When he finds there not there he goes to search for them. Cubbi wants to leave with him so he can become a knight.

When Cubbi claims he is serious about Calla's knighthood from "Up, Up & Away", the annoyed Gummis suggest he go into the forest to be a hero. After saving some people, Cubbi gets the reputation as "the Crimson Avenger". Although Cubbi has done a good job by protecting people from a highwayman trying to rob them, the thief elects to move into Dunwyn Castle - along with chances for juicier crimes, which end up causing problems for Calla, Cavin and King Gregor.

When Cubbi claims he is serious about Calla's knighthood from "Up, Up & Away", the annoyed Gummis suggest he go into the forest to be a hero. After saving some people, Cubbi gets the reputation as "the Crimson Avenger". Although Cubbi has done a good job by protecting people from a highwayman trying to rob them, the thief elects to move into Dunwyn Castle - along with chances for juicier crimes, which end up causing problems for Calla, Cavin and King Gregor.

Trolls try to hijack a shipment of gold protected by Sir Gawain. Cavin pleads for the Gummis to help, as Sir Gawain is not only Cavin's grandfather, but was also the person who discovered Zummi's medallion.

Duke Igthorn hires a bounty hunter to catch a Gummi Bear. When he refuses to pay, the hunter locks up Ightorn, the ogres, and Cubbi in his castle.

Zummi finds a section of the Great Book of Gummi that contains advanced magic spells. However, this also signals Zorlok, an evil wizard whom the Great Gummis had imprisoned in a subterranean prison, that he can find the unlocking spell, then be free to inflict violence on all Gummi Bears the world over, then conquer the world. To do this, Zorlok creates a monster to steal the Great Book, causing Zummi, Grammi and Gruffi needing to track it down.