Trex has got toothache so simon takes his huge dinosaur to the city's only vet, Hugo af Kattsvans. When the vet finds a hole in Tre's tooth, it all ends with not just Trex being in pain.
Simon is waiting for his favorite magazine to come. Unfortunately, the postman Snotty Kuvertsson is very thieving and Simon, together with Trex, takes up the fight to steal the comic book back.
Trex misses his relatives and in a desperate attempt to comfort his pet, Simon takes Trex to the library. Unfortunately, the dinosaur-hating librarian Sccccharlotta Tystensson works there and Trex has to try to sneak in.
Simon comes home to an empty fridge and has to go out in search of food with his tame dinosaur. At the hamburger stand, they trick the owner Big Jack by dressing up as a cowboy and horse. Unfortunately, Trex is not so good at playing horse
Simon wants to play tennis, he discovers that all the tennis balls are in Trex's stomach. Unfortunately, Trex is still hungry and drinks a whole jar of laxatives at the vet. Everything ends well except for the veterinarian.
