It's a new year at St Hope's and there's a host of new faces joining the highly-trained teenage secret agents at MI High. Geeky but gorgeous spy Rose is joined by two new sidekicks - wise-cracking, high-kicking gymnast Carrie and master-of-disguise Oscar, who is harbouring a mysterious secret.

Masterminding the teen spies from MI9's headquarters, deep beneath an innocuous comprehensive school, is new team leader Frank London with a wealth of espionage experience from his training role at MI9. Under Frank's command, the spies' mission is to protect Britain from threats to national security concocted by the evil Grand Master and his Secret Kriminal Underground League (S.K.U.L.).

This time, the threats are deadlier than ever. With the risk to the country now at an all-time high, the young spies must use their wit, intelligence and amazing talents to foil the bad guys.