Dead Wrong — Gillian Larkin

A short mystery with ghosts.

Grace Abrahams helps ghosts who can't move on until their problems have been solved. The ghosts she meets are attached to items found at storage locker auctions.

Vince is the ghost of a young man who is attached to a coffin. He's confused when he appears to Grace, and can't remember the details of his life, although he does recognise the coffin. He jokes that he might be a vampire.

His joke turns sour when his personality abruptly changes and he's transformed into a nastier version of himself. And this version is intent on causing Grace harm.