Pyramids — Fred Saberhagen

Tom Scheffler knew that his great-uncle, Montgomery Chapel, had made his fortune by selling ancient Egyptian artifacts that were finer than those in any museum. Scheffler also knew that -- fifty years later -- Chapel was still afraid of some man, some entity, known only as Pilgrim.

What Scheffler didn't know -- and would learn the hard way -- was that Pilgrim was coming back, aboard a ship that traveled both space and time, headed for a confrontation in a weirdly changed past where the monstrous gods of ancient Egypt lay in wait for grave robbers from out of Time...