In "Bassie and Adriaan: De Verdwenen Kroon", the story starts with the bad guys, de Baron, B2, and Vlugge Jaapie, getting out of jail and going straight back to their old tricks. They steal a really important crown and hide out in an old castle. They try to get money for the crown and set a trap for Bassie and Adriaan, making it look like they are the bad guys. Bassie and Adriaan escape the trap and have to prove they didn't do it. With the help of their robot Robin, they find out where the bad guys are hiding. There's a lot of back and forth, with the bad guys trying to get away and Bassie and Adriaan trying to catch them. In the end, they catch the villains and prove they're innocent, and the bad guys go back to jail.