Beautiful, bold, and brilliant Avery dreams of becoming a member of the Royal Astronomical Society—and the only way she can join the all-male society is to disguise herself as a boy. After helping Giles, Lord Strand, escape a disastrous engagement, she is certain he will assist in her daring masquerade. No lady would ever come up with such a preposterous scheme, and no gentleman would accept…but fortunately for Avery, Giles is no gentleman.

A bargain is struck between the stargazing adventuress and society's most sophisticated lord. He will sponsor her as his prodigy and she will cover for him as he hunts London's darkest warrens for a missing colleague from his shadowy past. But time and again, Giles finds his quest compromised by his fierce and unwise attraction to the lovely girl who, though no lady, may well be the one dame to finally unlock the secrets of his heart.