The Wren Enigma by John Broughton

After Dr. Amelia Evans’s friend is murdered in a Wren-designed church in Central London, DCI's Vance and Shepherd are called in to investigate the case.

They discover that Evans had stumbled across a centuries-old secret about the Philosophers’ Stone, and that there are unscrupulous people who will stop at nothing to get their hands on it.

The doctor's life is threatened by rogue Freemasons, and she also needs to fend off those who would save her. Resolving the Stone's Enigma could bring her a professorship and the Nobel Prize, but at what cost?

A compelling crime mystery, THE WREN ENIGMA is the sixth book in John Broughton's Vance And Shepherd Mysteries series.