As the turbulent year turns, Joanna makes some New Year Resolutions - for Roger - and suggests their marriage needs a re-boot. 'Out the door?' is his response.
The audience joins them as Joanna breathily compliments Roger, "How do you get it so perfect every time?" His reply - "Hot goose fat and regular tossing" - reveals that they are enjoying his signature roast potatoes. They're spending a quiet Christmas with Peter and Sally, but this snowballs into an extravagant house party when Peter is offered a rich friend's country pile and invites other couples.
Series 4 sees the long-married loving couple dealing with a new, young rescue dog, a feisty old auntie, handing out advice to friends and godchildren - and sailing away into the sunset.