The Eye of Ra by Ben Gartner

Exploring a mysterious cave in the mountains behind their house, John and his sister Sarah are shocked to discover they’ve time traveled to ancient Egypt! Now they must work together to find a way back home from an ancient civilization of golden desert sand and a towering new pyramid, without parents to save them. The adventures abound—cobras, scorpions, a tomb robber, and more! The two kids have to trust each other, make friends who can help, and survive the challenges thrown at them . . . or be stuck in ancient Egypt forever. For readers graduating from the Magic Tree House series and ready for intense action, dive into this middle grade novel rich with meticulous historical detail.

Sol Invictus (The Eye of Ra Book 2) by Ben Gartner

Siblings John and Sarah barely made it home last time, but in their next time traveling adventure the challenge really heats up. Surrounded by clashing cultures on the ancient Roman frontier, they must fulfill their quest to unite the emperor with his enemy, an Alemanni barbarian, or risk being stuck in time forever. An action-packed fantasy full of sword fights, chariot chases, fearsome wild animals, and high mountain survival. For graduates of the Magic Tree House looking for a thrilling middle grade page-turner, read Sol Invictus, book two of The Eye of Ra series!