It all started when a suspicious looking briefcase was delivered to Year 5!  Who delivered it?  How did they know that Year 5 were learning to be spies?  The briefcase contains a variety of objects and a coded letter.  Luckily, Year 5, have learnt how to use a Cipher Wheel, which has helped them to decipher the message!  The mission has started - they have just three weeks to carry out their investigations ....