It's Blue Peter's first visit to spy school to meet the eight candidates selected to join the Project Petra mission. They'll be tested on key observational and analytical skills over a series of tough challenges, as only three can ultimately make it as CBBC intelligence officers and gain unprecedented access to MI5! All that and the Amazing Bubble Man, Louis Pearl joins us in studio to demonstrate the art of blowing bubbles, and Australian pop band Sheppard perform their brand new single. Don't miss it!