Dr Chris and Dr Xand reveal how salt is the magic ingredient that enables you to sweat in a lab experiment, and Dr Ronx finds out how gene therapy is helping treat patients with immune disorders. The doctors head onto the wards in Ouch and About and find out how to confuse your left with your right in Body Tricks. Meanwhile, in the Emergency Department Reuben's broken his elbow and Isabelle's in with neck pain after falling off her horse.