This is the first book where vampires have traveled from an expedition from Mexico on board a ship to London. On arriving the threat to the capital spurs the quick partnership of Jack Harket, an orphan by the docks and Benedict Cole, a stowaway from the ship. Ben's father has been killed by the vampires. During the events they must discover how to stop their invasion as well as discover their weaknesses and are assisted by Benedict's sister Emily Cole.They eventually get the help of Professor Adensnap and find the blood rose a magical flower that can kill vampires.
After banishing all the vampires from London a trip to Paris by Jack, Emily and Ben uncovers that there are those that wake drained of blood if ever. The vampires have moved on and so must the fight if anyone stands a chance against the vampire god Camazotz.