Moonlight on the Sphinx — Barbara Cartland

Tony Burke, the son of Lord Birkenhall, persuades his sister Octavia to run away with him in order to avoid the debts left by their father. Tony plans to meet up with the girl he hopes to marry. But when they meet in Alexandria, there's no room for Octavia. Far to England, she found herself defenseless and alone on the hostile, exotic shores of Alexandria.

With no place to turn, beautiful and proud Octavia agreed to help the handsome renegade Kane Gordon, wanted for his secret knowledge of an ancient tomb and its vast fortune. Posing as the wife of the handsome stranger, she was soon sailing up the Nile Delta toward Cairo, and straight into a treacherous plot that would threaten her life--and the Crown!