Poppy Denby Investigates is a mystery series set in the 1920s about an investigative journalist called Poppy Denby.

Set in 1925, Poppy Denby is Arts and Entertainment Editor at the London Daily Globe newspaper. A chance meeting at a Royal Institution lecture in London leads Poppy to a visit Oxford to enquire about the accidental death of a young promising scientist Dr. June Leighton. While working in her crystallography laboratory examining a diamond in the basement of the old Ashmolean, Dr. Leighton was electrocuted and killed. Poppy is sent by her newspaper to write a story about Dr. Leighton whose promising career was cut short and a mystery unfolds. Will Poppy uncover the truth?

The Crystal Crypt is the SIXTH book in the POPPY DENBY INVESTIGATES series.