The Wild Thornberrys: The Origin of Donnie
Donnie goes missing and the rest of the Thornberry family have various adventures (broken bones, getting lost in a cave, and a forest fire) while looking for him. It has been screened as a TV movie and as four episodes in season 4 of the TV series.
Directors: Carol Millican, Dean Criswell, Joseph Scott, Ron Noble
Writers: Arlene Klasky, David Silverman, Gabor Csupo, Jeff Astrof, Joan Considine Johnson, Mark Risley, Mike Sikowitz, Sheila M. Anthony, Stephen Sustarsic, Steve Pepoon
Cast
IMDB: tt0327250