Publisher's Synopsis
The plot focuses on Adam Salton, originally from Australia, who is contacted by his great-uncle, Richard Salton, in 1860 Derbyshire[6] for the purpose of establishing a relationship between these last two members of the family. His great-uncle wants to make Adam his heir. Although Adam has already made his own fortune in Australia he enthusiastically agrees to meet his uncle, and the two men become good friends. Adam travels to Richard Salton's house in Mercia, Lesser Hill, and quickly finds himself at the centre of mysterious and inexplicable occurrences, with Sir Nathaniel as guide.The new heir to the Caswall estate (known as Castra Regis or the Royal Camp), Edgar Caswall, appears to be making some sort of a mesmeric assault on a local girl, Lilla Watford. Arabella March, of Diana's Grove, seems to be running a game of her own, perhaps angling to become Mrs. Caswall. Edgar Caswall is a slightly pathological eccentric who inherited Mesmer's chest which he keeps at the Castra Regis Tower. Caswall wants to recreate mesmerism, associated with Franz Mesmer, which was a precursor to hypnotism. He is obsessed with Lilla Watford, and attempts to break her using his mesmer. Fortunately, with the help of Lilla's cousin Mimi, he is thwarted time and again. Caswall orders a giant kite in the shape of a hawk built to scare away pigeons which have gone berserk and attacked his fields and destroyed his crops. For lack of anything better to do he obsessively watches the kite and begins to believe that it has a mind of its own and that he himself is a god.Adam Salton discovers black snakes on the property and buys a mongoose to hunt them down. He then discovers a child who has been bitten on the neck. The child barely survives. He learns that another child was killed earlier while animals were also killed throughout the county. Caswall's servant, Oolanga, an African man obsessed with death and torture, prowls around the estates, glorying in the carnage left by the White Worm. Adam's mongoose attacks Arabella, who shoots it to death. Adam procures more mongoose and keeps them locked in his trunks when not using them to hunt. Arabella tears another mongoose apart with her hands. Caswall's servant takes a peculiar liking to Arabella, perhaps sensing something violent in her. Arabella scorns Oolanga's advances and is deeply insulted that he would dare approach her. In an attempt to win her over, Oolanga steals one of Adam's trunks (which he believes is filled with treasure, but is actually just another mongoose), and Adam follows Oolanga. Arabella lures Oolanga to a deep well in her house, then murders him in rage and disgust, by dragging him down into the deep pit tunnelled through a bed of white china clay. Adam witnesses the murder which he cannot prove, and Arabella writes him a letter the next day with the previous night's events twisted to claim her innocence. Adam and Sir Nathaniel begin to suspect Arabella guilty of the other crimes.