Jack and Annie have met knights, pirates, ninjas, and Vikings, but they have never met the most fearsome warriors of all: Roman soldiers. When the magic tree house whisks them back to the early 100s AD, Jack and Annie find themselves in a Roman camp. Their mission: . That is easier said than done! The Roman soldiers are much scarier in person—and suspicious of strangers. Then a mysterious man riding a black horse gives Jack and Annie some advice to help them on their mission. But the man may not be who he seems. Will Jack and Annie be good warriors? Can they learn what makes the Roman soldiers so great? And who is the mysterious rider . . .? Merlin Missions: More challenging adventures for the experienced reader Fact Trackers: Nonfiction companions to your favorite Magic Tree House adventures If you're looking for it was renumbered as part of the rebrand in 2017 as Merlin Mission #3.