It is now spring 1939 and a potential world war looms. Tristan is now a qualified vet, while James enters a new stage of his life with Helen and at the practice. After being made joint business partner by Siegfried, James pushes to take on more responsibility via the Ministry of Agriculture's new bovine TB testing scheme, but its unexpected challenges risk pushing him to breaking point.

Everyone is trying to get along as best they can in the face of changes at Skeldale House. Helen has moved into the bedsit upstairs with James.

Siegfried receives some difficult news and becomes even more irascible than usual. Helen gets a new insight into how hard James works, but feels reluctant to help him by asking her father.

Tristan decides that he is outgrowing running the small animal surgery and a shock departure from Darrowby brings James's feelings about his place in Darrowby to the surface for Helen.

Siegfried and Tristan are left in charge of Skeldale House, when Mrs Hall takes time off to meet up with an important person from her past.

Everyone at Skeldale House is pushed to think about what matters to them most when the radio reports that Britain is standing on the brink of war.

It's Christmas in Darrowby and everyone is trying to make the most of things while the world is at war. A young guest brings some wonder, mischief and cheer to Skeldale House while everyone waits for important news. When Mrs Pumphrey heralds the arrival of a kitten in need of extra care at Pumphrey Manor, James has just the person to take him under their wing. Siegfried is asked to pay a visit to an injured River just before a big race and makes an important discovery which Sebright Saunders uses as leverage to get the horse back on the racetrack