What should have been a routine investigation into a cold case of a ghostly student's murder leads Harry 'The Hammer' Potter-Mason back down a dark road where he finds himself the right wizard at the wrong time in the right place to see his peers petrified one by one. THIS IS A SEQUEL TO THE CASE OF THE CINTAMANI STONE!

Petunia married a Scotland Yard detective named Grant Mason and Harry's grown up obsessed with Film Noir and being a Detective. So much so he's adopted a nickname and now he's Harry 'The Hammer' Potter-Mason.