City of Gold and Shadows — Ellis Peters

When Alan Morris disappears, his great niece Charlotte regrets never having got to know her archaeologist great uncle better. And, in an attempt to remedy that deficiency, she goes to visit the Roman site of Aurae Phiala, on the Welsh border, that he had spent so much time investigating.

When she gets there, Charlotte finds more than just a few old stones...

First there is a charming young man, coincidentally staying in the same hotel, who is very insistent on being her guide. Then a troublesome schoolboy disappears and a corpse is found. And George Felse finds himself having to solve a mystery whose roots go back to ancient Roman times...