Reeling from the recent loss of his mother, Riley Harrison claims he has seen a real dinosaur, to which his dad Wyatt Harrison and love interest Dr. Starr quickly write it off as a coping mechanism for his grief. Villians, Mr. Bigg and Dr. Vandersaurean responsible for the creature and its accidental release, try in desperation to recover it and capture young Riley before the public finds out about their diabolical plans.