Sealgairean Spòrsail/History Hunters S01E17 - Brathadairean/Spies

In today's programme, the History Hunters go undercover and take a look at the gadgets and tactics used by spies. Their first mission is to make a homemade periscope to spy on their little sister. She is talking about them on the phone - but what is she saying and who is she talking to? Next up, they must create a secret spy note using invisible ink to draw a map pointing Agent X to the location of some secret spy chocolate. Back in the studio, Calum and Kerry Anne use everyday items to make spy gadgets such as a book safe, and a note hidden in an olive.