The series revolves around Danger Mouse, the "world's greatest secret agent", and his hamster sidekick Penfold, who protect the world from a variety of dangers. With help from his boss Colonel K and the genius scientist Professor Squawkencluck, Danger Mouse is equipped to defeat his nemesis, Baron von Greenback. Within three weeks of the series running, Danger Mouse achieved 2.4 million viewers and became among the highest rated shows on CBBC.