Identical twins Dr Chris and Dr Xand van Tulleken experiment and explore their way through the fascinating world of medicine and biology. Chris and Xand will let the viewer in to their exclusive world of medicine and explain the awesome things our bodies can do. The doctors experiment on their muscles to show how they work. Dr Chris meets some wriggly maggots that are helping to heal a sore foot, and Dr Xand goes on call with an emergency ambulance team. Meanwhile, over in accident and emergency, one patient has some grit in his head after a fall in the playground and another has injured his neck after performing a karate kick.

Identical twins Dr Chris and Dr Xand van Tulleken experiment and explore their way through the fascinating world of medicine and biology. The doctors show what really happens when you sneeze! Dr Chris gets his hands on a real human brain and Dr Xand goes on call with an emergency ambulance team. Meanwhile, over in accident and emergency, one patient has a hook caught in their hand and another thinks he's lost a toenail up his nose.

The doctors demonstrate how our body movements are controlled by confusing their own brains. Dr Chris lets a blood-sucking leech feed on his arm and Dr Xand goes on call with an emergency ambulance team. Meanwhile, over in accident and emergency, a patient has locked their jaw wide open and another needs stitches after a particularly nasty fall.

The doctors see how much pain they can take in their laboratory, Dr Xand investigates how our shoes can dramatically change the way we walk and Dr Chris goes on call with an emergency ambulance team. Meanwhile, over in accident and emergency, a patient comes in with a suspected hand fracture and another may lose his fingernail after trapping his finger in a car door.

Dr Chris inserts a special medical tube into Dr Xand's nose and down to his belly to prove that the nose, mouth and stomach are all connected. Dr Xand takes things to the extreme as he endures a room colder than Antarctica to find out how our bodies cope in freezing temperatures. And Dr Chris is in the operating theatre to see an incredible robot surgeon perform a real-life surgery. Meanwhile, over in accident and emergency, one patient has a broken elbow after a game of leapfrog goes horribly wrong, and another has managed to get a stone stuck in his ear.