In an alternate England of 1851, while taking her friend Sidheag by train to her werewolf pack in Scotland, fifteen-year-old Sophronia uncovers a plot that threatens to dissolve all of London into chaos and must decide where her loyalties lie once and for all.

In 1807, having survived a typhoon in the East Indies, Jacky Faber makes her way to London to seek a pardon for herself and her betrothed, Jaimy Fletcher, who, posing as a highwayman, is trying to avenge her supposed death.

Preferring adventure to an arranged marriage, the sixteen-year-old daughter of Queen Victoria's royal surgeon sneaks out to swordfight with two friends when the three are mauled by what looks like rabid dogs.

In 1868, with his army officer father suddenly posted to India, and his mother mysteriously "unwell," fourteen-year-old Sherlock Holmes is sent to stay with his eccentric uncle and aunt in their vast house in Farnham, where he uncovers his first murder and a diabolical villain.

In 1868, teenaged Sherlock Holmes discovers that his American tutor is hunting a notorious killer who was supposedly killed by the United States government, but who is apparently alive and well in Surrey, England.

Sixteen-year-old Violet Willoughby has been part of her mother's Spiritualist scam since she was nine, but during an 1872 house party in Hampshire, England, she is horrified to learn that she can actually see ghosts, one of whom wants Violet to solve her murder.

Sixteen-year-old Gwen, the newest and final member of the secret time-traveling Circle of Twelve, searches through history for the other time-travelers, aided by friend Lesley, James the ghost, Xemerius the gargoyle demon, and Gideon, the Diamond, whose fate seems bound with hers.

Rescued from the gallows in 1850s London, young orphan and thief Mary Quinn is offered a place at Miss Scrimshaw's Academy for Girls where she is trained to be part of an all-female investigative unit called The Agency and, at age seventeen, she infiltrates a rich merchant's home in hopes of tracing his missing cargo ships.

In 1919, independent-minded fifteen-year-old Rosalind lives in India with her English parents, and when they fear she has fallen in with some rebellious types who believe in Indian self-government, she is sent "home" to London, where she has never been before and where her older brother died, to stay with her two aunts.

While traveling through early seventh-century Britain trying to stop an impending war, Essa, who bears the blood of native British tribes and of the invading Anglish, makes discoveries that divide his loyalties.