On the edge of the Great Valley stands mysterious Saurus Rock and twin Threehorns, Dinah and Dana, have run away to find it. Could the mysterious Longneck named Doc be the famous Lone Dinosaur? To find out, Littlefoot and friends must cross the Great Valley and face a dangerous Sharptooth themselves! Along the way they learn about change, acceptance and responsibility.

Originally released as a motion picture in 1998. Special features: Littlefoot's playhouse; "Crossing the chasm" game; rebuilding Saurus Rock game; sing-along-songs; DVD-ROM features include cool coloring pages and fun activities.