S4, E3: PC Penhale is delighted when his beloved older brother Sam comes to visit. When Sam offers to re-paint the surgery, Martin observes him and concludes that he may have a rare genetic disease, but a blood test discloses something unexpected which could alter the brothers' bond forever. Meanwhile, Al acts on some relationship advice from Bert but things go from bad to worse with Pauline.

Starring John Marquez, Ewan Hooper, Martin Marquez