An online summary for "The Egypt Game" by Zilpha Keatley Snyder is available at the Professional Development Institute website. The novel, which was published in 1967 by Atheneum, has won several awards, including First Prize in the 1967 New York Spring Book Festival.
The story follows two very different schoolgirls, Melanie Ross and April Hall, as they bond over a shared interest in ancient Egypt. Eventually, the two initiate the Egypt Game of the title, gathering additional players over time.
This imaginative role-playing game starts harmlessly enough, but it soon develops into something stranger and more sinister, involving intrigue and a local murderer.