Audrey Hudson has been a werewolf all her adult life, but after the terrible, unsolved slaughter of her found-family in Edinburgh, she withdraws to London, where a collector of cryptid artefacts kidnaps her.

Luckily, a young detective named Sherlock Holmes rescues Audrey, and although oblivious to the existence of werewolves and ghosts, he's convinced he can find out who killed her family.

She offers the awkward genius a room in her Baker Street house, if he can find someone to share with. Enter John Watson - and his best friend Nicola 'Nick' Murray - whose own cryptid encounters will have a significant bearing on the inhabitants of 221B.

Of course Sherlock's investigations suggest a much bigger mystery is at play: one involving a disturbing case on Dartmoor with a Greek interpreter; Sherlock's agoraphobic sister, Myca; Audrey's long-dead love, Ruby Stockton; and the fate of Great Britain's mystic heart.

Will Holmes and Watson be able to unravel the mysteries that have haunted Audrey's life?

Can Audrey protect her new pack, or will she again lose those she loves to unknown enemies?