The doctors prove that we all have invisible ink inside our bodies, and Dr Xand sees head lice removed from someone's hair with a vacuum cleaner. Meanwhile, over in accident and emergency, one patient has banged her head on a telegraph pole and another has a piece of crayon in her ear...

The doctors show that your breath is just as unique as your fingerprints, and Dr Chris goes behind the scenes of medical drama Casualty to see how they make fake body parts look so realistic. Meanwhile, over in accident and emergency, one patient has a nasty infection on his cheek and another has something stuck in his ear!