The Brook Randall School for Girls of Military Parentage is a boarding school of good reputation. For teenagers Melanie Mackenzie, Joan Vere d'Urquart, and Laura MaCallaman, it is a tranquil and ordered environment that allows them to overcome the tragedies of their pasts.

But when the famous playwright Christopher Marlowe arrives at the school to give a lecture on historical time travel, bringing with him an air of mystery and adventure, the delicate equilibrium of Randall's is shattered.

Melanie, it turns out, is a Time Walker: someone who can break the barriers of time and send people back into the past. She is just what Marlowe has been looking for - someone who can return him to his own time and allow him to escape the religious fanatics who have hunted him since the Elizabethan era.

But as events unfold, both Christopher Marlowe and the girls find themselves embroiled in a historical time travel mystery spanning the 1600s to the closing days of the Napoleonic Wars.