"Theodosia and the Staff of Osiris" by R.L. LaFevers (Preowned Hardcover)

Theodosia Throckmorton is in a fix. Allowed to attend a reception given by one of the directors of her parents’ museum, she stumbles across Mr. Tetley of the British Museum—in most unusual circumstances! Since Theo has last seen him in a showdown in an ancient Egyptian tomb, his reappearance could mean only one thing: the Serpents of Chaos are back.