London’s street of booksellers – labyrinths of shelves, shops full of stories on yellowed pages. Mercy Amberdale manages her stepdad’s antiquarian bookshop and practices book magic. When she is forced to send the last chapter of the lost message in a bottle book to the shady Mister Sedgwick, the world of Bibliomancy is thrown out of joint. Poisoned books and nightly rituals, a magical airship and a mysterious marquis – Mercy gets caught up in a whirlwind of deadly intrigues. For whoever unites all chapters of the message in a bottle book will be able to tear down the boundaries between reality and fiction. If Mercy does not manage to stop her enemies, her world is in danger of facing its end – and the antagonist’s invasion.