Colonel K sends DM and Penfold undercover on a mission to the mysterious Island of Villainy in order to discover what the Baron is up to and what happened to their colleague Danger Sheep. They quickly discover that DS has turned to the villainous side and find themselves in a competition to become the Baron's new sidekick. A disguised DM is terrible at being bad and his competitive streak can't cope with losing at any contest. He goes head to head with Danger Sheep as to who can be the best bad guy threatening to blow their cover and fail the mission. Danger Mouse must learn to lose otherwise the world is doomed!

Another ‘grate' episode on Tuesday sees fanatical cheese fundamentalist Aubrey Camembear threaten to create the ultimate weapon which will turn everything to cheese.