The Pirate River has touched the world of Marrill again! The girl received a creepy message: “The Iron Tide is approaching!” This means one thing - our entire world is under threat of extinction. Marrill is determined to take the dangerous journey across the River and prevent disaster. Reuniting with Finn and the rest of the crew on the Kraken, Marrill learns that they are heading to the city where, according to legend, the Wish Machine is located. An ancient artifact capable of fulfilling any desire. Murrill wants to save his world. And Fin dreams that people will stop forgetting him. Whose desire will outweigh? Which of them will be the first to get to the Wish Machine? Is it really necessary to sacrifice the most important thing - friendship - in order to fulfill a desire?!