Piet Piraat hopes to join the Brave Pirate Club. To do so, he must complete three assignments. The last to do of these assignments is to defeat a sea monster. The Scheve Schuit sets course for the port town of Comino, where they will try to free the townspeople from the threat of the so called sea monster...

100 years ago, evil Captain Snorrebaard was cursed by putting an enchanted crown on his head. He turned into a painting and his ship sank, along with the crown, to the bottom of the sea. Piet Piraat and his crew find the floating painting and think that it could help them find a hidden treasure, but Captain Snorrebaard has something more sinister in mind...

After a heavy storm, the grumpy Captain Eksteroog ends up on an uninhabited island. To spare the time, he decides to search for a treasure that his arch-enemy Zilvertand once buried there. Captain Eksteroog soon notices that he is not alone. Reus, a big guy of two meters and five children with their dog Smikkel have also ended up on the island. Captain Eksteroog and Reus capture dog Smikkel and force the children to search for the treasure. Meanwhile, Piet, Berend, Stien and Steven discover an island that is not on any of their maps. They go on an investigation and end up on the same island where Captain Eksteroog's resides! When they find the children there, they decide to help them find the treasure. But what if they find it and Captain Eksteroog still won't let them leave?