The Hippopotamus Pool by Elizabeth Peters

Amelia Peabody and her husband Radcliffe Emerson, aided by their clever son Ramses and a cast of devoted colleagues, return to Egypt to untangle a web of thefts, murders, and smuggled antiquities that points to a long-hidden tomb and a treacherous mastermind; blending scholarly sleuthing, desert adventure, wry domestic comedy, and revelations about past loyalties, they race to protect priceless finds and their family while unmasking those who profit from the past.

Purchase from Bookshop.org