Peter meets immigration officers Matt Dyson and Tim Weatherall, who explain what a passport says about a person and how they can be sure you are who you say you are.
He also learns about the unseen techniques used to flush out those who attempt to smuggle drugs by swallowing them.
He is put through one of the machines used to detect drugs and is shown the largest X-ray machine in the world.
Peter meets the unseen bank staff who spend their days watching our spending habits and alerting us to possible fraud when our usual spending patterns are broken.
He then uses his bonus points card at a supermarket, which prompts him to question who knows what about his buying habits and how this information helps analysts to persuade him to spend more, by targetting him with tailor-made and tempting offers.
Peter meets the unseen bank staff who watch our spending habits.
Peter meets forensic scientists and talks to them about their work.
A 'questioned documents' specialist examines Peter's signature and reveals some of its secrets, and Peter also learns about some of the methods used to match crime scene marks with suspected shoes and tools.
Plus Peter Dean, a police doctor and television consultant, discusses real crime compared to what we see on TV programmes.