Bon and Ream become stranded in the future while on a dangerous mission to rescue a "Time Tripper." Will they be able to find their way back home?

In 3319 B.C. Sumer, a young boy develops the beginnings of an ancient writing system — but his village is under threat from raiders and needs protection.

The crew saves an older man in 14th-century France from the plague. Later, after learning that he's still in danger, they launch another rescue mission.