World of the Orb - Michael Thompson - Bog

Best friends Marvin and Andy have just discovered the Museum of Natural History's unnatural secret: The Orb, a mysterious relic that plunges these two modern teens into a medieval world of monsters, myth, and magic. To return home, they must embark on a global treasure hunt to unite five elemental crystals, all while eluding the eye of a tyrannical warlock bent on conquering the Realms. This isn't the field trip they expected...