A baby dinosaur is brought into the present time and the Smurfs try to get him back by a magic key. This the first part of the story arc which also includes "Cave Smurfs". This episode was originally featured as a three-part episode and was later broken into two separately titled episodes when it was aired in syndication. Parts 1 and 2 were combined into a single episode, retaining the original title, while Part 3 became "Lost In The Ages".
Elenco: Don Messick , Lucille Bliss , Frank Welker , Michael Bell , June Foray , Paul Winchell , Danny Goldman , Hamilton Camp , William Callaway .