WARNING: Medical procedures - viewer discretion is advised. Part 1 of series. In this episode, Alice meets party girl and mum of two Grainne, who, at nearly 40 and with a family history of diabetes, is stressing her kidneys. Grainne visits the lab to discover more about the body's filtration system and helps dissect a kidney to see the internal workings for herself. Armed with the information, she finally plucks up the courage to take a diabetes test. Alice also puts three rugby players through their paces to find out how their kidneys cope under the stress of dehydration, and June from Aberdeen in Scotland speaks from her own experience about what happens when kidneys fail. She's been on dialysis for four years, and her sister, Lorraine, offers her own kidney. When it is found to be a match, the programme follows the live transplant operation, but the procedure isn't straightforward and the surgeon has to make a tough call.