It is late Spring when Wally, Jeremy, Shades and Mario are at the La Brea Tar Pits working on a school research project and discover a mysterious tar egg that cracks open to reveal a friendly dinosaur.

Denver follows Jeremy to his job at the supermarket, where he hides in the storeroom and stuffs himself full of potato chips.

While camping at a mountain lake with the boys, Denver is mistaken for a horrible lake monster.

The boys decide to do a science project on dinosaurs for the school science fair.

Wally's first day on the job at the zoo takes a turn for the worse when the self-serving Dr. Funt captures Denver for his new high-tech exhibit.

While visiting Jeremy's Uncle Eli on his Nevada ranch, Denver and the boys attend a local rodeo.

When Heather gets a job at a Dinosaur theme amusement park, Denver roams freely around the park and fits right in with all the dino-costumed employees.

Shades develops a recent interest in karate. He is also very into Nikko, the daughter of his instructor.

When Heather and Wally's parents inform the two that they are expecting guests from out-of-town, they must hide Denver that the local movie theater, which is believed to be haunted.

When the boys enter Wally's dog, Rocky, in a relay race for dogs, they also disguise Denver as a dog so that Rocky will perform well.

When disreputable treasure hunters kidnap a valuable dolphin from a marine research facility and use him to locate sunken treasure, Denver dives in to save the dolphin.

Heather and the boys take Denver to a mountain ski resort.

To help Wally in his predicament with Johnny Price, a practical joker who continually torments him, Denver uses his magic tar eggshell and shows Wally a time in his own life when he was tormented by the Pteranodon, and Wally is able to become friends with Johnny Price.

No one anticipates the trouble that arises when one of the charity items collected for the school auction turns out to be a silver scepter belonging to Bertha Bird and her two sons.

Disguised in a Chinese lion headdress and robe, Denver leads a mad chase for dognappers through Chinatown during the Chinese New Year Parade.

In an embellished story of Jack and The Bean Stalk, Denver buys some magic corn kernels from Morton Fizzback, plants them, then climbs the giant stalk to arrive at the castle of the giantess (Bertha Bird).