The film recounts the adventures of Julian, Dick, Anne, George and Timmy the dog on their first holiday together at the seaside. In an old smugglers' cave, the children happen to overhear a radio message that refers to the abduction of George’s father Quentin. The professor has set up a laboratory on Kirrin Island where he’s doing research on a new energy generation method. Someone has obviously taken great interest in the valuable research results. But neither the police nor George’s mother Fanny believe the children. They are now on their own and discover a conspiracy that almost takes their breath away.

For their bicycle tour to Catmoor, the friends Julian, Dick and Anne, their cousin Georgina, called George, and her dog Timmy have long looked forward to. But the camping holiday in the countryside ends with the kidnapping of Dick, confuse the two underprivileged hoodlums with the same age millionaire's son Hardy. With sophistication and courage, the five friends take on his trail that leads from a mysterious traveling circus to the castle "Owls Nest" where the kidnappers force Dick to coax the clue to a giant emerald.

In their third cinema adventure the Famous Five are searching for a pirate treasure...

The famous five George, Julian, Dick, Anne and Timmy the dog are spending holidays together. But when they are invited by Berhard, father of Julian, Dick and Anne, to visit an egyptian exhibition they see a burglar. They have a look at the mummy the burglar was tempering with to find a golden amulet. The famous five decide to visit Egypt to hand over the amulet. When arriving in Egypt Bernhard is arrested because he's asserted he stole the amulet and replaced it with a fake. Now its up to the young detectives to solve the case and prove their fathers innocence.

En route to a party they are not keen on attending, the Famous Five are almost relieved when Aunt Fanny's car breaks down, stranding them in a small town. To pass the time, they visit the local natural history museum, where some newly-discovered dinosaur bones are being unveiled. Here they meet Marty, who tells them that his father, long dead, supposedly found a complete dinosaur skeleton and made a map of its whereabouts. Unfortunately the map has been stolen. Unable to let a good mystery go unsolved, George, Julian, Dick, Anne and Timmy, join a guided hike through the Valley of Dinosaurs. But their fact-finding mission soon turns into a race to find the dinosaur when they suspect that the thief is one of the group.