Guns in the Heather
Guns in the Heather is a 1969 Walt Disney family film directed by Robert Butler and produced by Ron Miller. It stars Kurt Russell, Glenn Corbett and Alfred Burke. It was originally broadcast in parts on Walt Disneys Wonderful World of Color in the United States under the title Guns in the Heather, then reedited for a European theatrical release under the English title, The Secret of Boyne Castle. It was rebroadcast on American television in 1978 under the title The Spybusters. The story is based on the 1963 novel Guns in the Heather, by Lockhart Amerman.
Source: Wikipedia
