Siegfried bumps into Mr. Beresford, the manager of the local bank whose dog behaves badly in the car. Tristan woos the lovely Marjorie Simpson and Siegfried meets Sarah Raworth. James treats the elderly Mr. Bailey's dog who has developed a bad case of bronchitis and Siegfried criticizes James when he waives the fee. Siegfried, however, has trouble following his own advice. Tristan rescues a severely injured cat and then convinces James to treat him rather than put him down. Helen promptly adopts him and nurses him back to good health but is devastated when she learns the cat belongs to the Gibbons family. Everyone celebrates Tristan's birthday.

Tristan has had a rather late night and Siegfried takes him to task over his bad habits. Tristan announces that he has a steady girlfriend, Deborah Mount and will reform his wild ways. Turns out Deborah's father doesn't know anything about the relationship and may not approve. When he does hear of it, he has serious doubts about Tristan's character. Tristan doesn't help his case with his silly pranks. James has several encounters with a street urchin, Wesley Binks, whom he'd earlier caught stealing. James nonetheless helps Wesley out when his dog contracts distemper. Siegfried reacts badly when the Weeting brothers tell him they are off to join the military.

The vets visit a modern dairy farm and are left to wonder who benefits from the cold efficiency. Miss Westerman returns with her dog Hamish and Tristan tries to avoid her, given that he misplaced her dog the last time she him in the vets' care. She is concerned at the rumors that all dogs will need to be destroyed if war is declared but Tristan sets her mind to rest. The vets agree to spay a cat for a minimum fee, but find they may have gotten more that they bargained for. Siegfried treat Herbie Hinchcliffe's aging horse Dolly and becomes emotionally involved in the case when he has to put

The Darrowby Bell Ringing Society is suspending its operations for the duration of the war and they have one, final "meeting" at the local pub. James and Tristan go to the bell tower with not unexpected results. The vets have to deal with a series of dog poisonings. They soon identify the farmer responsible, but not before several more animals die. Siegfried treats Joan Clifford's dog Saxon, but the case has very specific implications for her. James treats Mr. Hanson's pigs but it's Mr. Hanson who is most entertaining in that he always speaks at the top of his lungs.