It's about the area in Kenya that between world wars that was the home of rich, white mostly British expats who lived, loved, partied hard & died.
The author is a white woman who's family has lived near the area for at least 3 generations & she explores the history of the place though the old houses of the major & minor players in Happy Valley of the 1920s & 1930s. Along the way she tries to solve the biggest mystery of that time; who killed the Earl of Erroll in 1941? The case exposed more than a few secrets and was covered in James Fox's White Mischief.
She is helped by a local man with a passion for the environment who's considered crazy by just about every Kenyan for trying to protect the forests & local wildlife.
the book also touches on Kenyan independence & the Mau Mau uprising.
I liked the book and the stories she uncovered.