The Secret of Lost Valley While on a family outing, a boy, Adam, gets lost in the forest and discovers a wild boy there. Communicating by sign language, they become friends. When the wild boy is captured by scientists, Adam helps him escape. Details Casts Posters Title The Secret of Lost Valley Release Date 1980-04-27 Runtime 00 Hours 56 Minutes Genres Adventure Drama Family TV Movie Production Companies Walt Disney Productions Production Countries United States of America Gary Collins... Ned Harkness... Mary Ann Mobley... Susan Harkness... Brad Savage... Adam Harkness... Eddie Marquez... Zane... Jackson Bostwick... ... John Lupton... ... Tom Simcox... ... Barry Sullivan... ... Original Size (800x1200)