When Stark enlists the help of The Grandmistress as an MI9 business advisor, she seizes the opportunity to escape and leaves all Stark's agents stranded in the Himalayas. Meanwhile, at St Hope's Rose is upset when Scoop borrows her new model rocket the 'X48' and promptly breaks it. Frank and the spies remember that the Grandmistress used to run a toy factory and the team head out there hoping to catch her. As Frank and Stark watch with horror from HQ, Rose, Carrie and Oscar are captured by the Grandmistress. With every other MI9 agent stranded up a mountain and fearing for the safety of his team, Frank suggests a risky idea: turning three ordinary school pupils into MI9 agents using an invention called Smart Ease, a compound developed by MI9 in the 50s to dramatically speed up agent training. Stark reluctantly agrees to let Frank go ahead with the scheme and they administer the Smart Ease at random to three St Hope's pupils. MI9 has a new 'B Team': Avril, Davina and Scoop! Despite the B Team's initial reluctance, when they learn that their classmates are in trouble they agree to help and hurry to the toy factory in search of our spies. Meanwhile, Rose, Oscar and Carrie find themselves in a warehouse with the Grandmistress, standing next to crates packed full of X48s. Suddenly the Grandmistress flicks a lightswitch to reveal a huge rocket, a full scale replica of the X48 model... except this one has a bomb strapped to it! The Grandmistress locks the spies inside the warhead and sets a timer on the rocket. Can the B Team get there in time to stop the rocket launch, rescue our spies and save the day?