Siegfried's younger brother Tristan joins the practice after graduating from Edinburgh veterinary college. James finds himself begrudgingly taking the new arrival with him on his rounds, which leads to a disastrous clash of over how to treat a cow suffering from milk fever. On their return to the practice, they find that Mrs Hall has guessed that Tristan is not being entirely honest about his sudden arrival. Elsewhere, James makes a good impression on a wealthy widow and her beloved Pekingese.