Busman's honeymoon

Dorothy L. Sayers

Lord Peter Wimsey and Harriet Vane marry and go to spend their honeymoon at Talboys, an old farmhouse in Hertfordshire which he has bought her as a present. The honeymoon is intended as a break from their usual routine of solving crimes (him) and writing about them (her), but it turns into a murder investigation when the seller of the house is found dead at the bottom of the cellar steps with severe head injuries. - Wikipedia.