Identical twins Dr Chris and Dr Xand van Tulleken experiment and explore their way through the fascinating world of medicine and biology. Dr Chris takes a terrifying, stomach-turning ride in an aerobatic display plane to explain what happens to your body when you feel travel sick. The doctors put on their pyjamas to investigate all about sleep, and Xand finally finds out if he really does snore! Also, Dr Chris goes on call with an emergency ambulance team. Meanwhile, over in accident and emergency, one patient is suffering from mysterious tummy pains and another has an injured hand after an accident involving a race in a high-heeled shoe!