Walt Disney's 3-part made-for-TV feature, The Secret of Boyne Castle (1969), originally shown on "Walt Disney's Wonderful World of Color" (the new title for "Disneyland"), re-edited into feature film form for European theatrical release.
A young American studying in Ireland, Rich Evans, becomes involved with Russian agents and a defecting scientist, after he hears a warning from a dying man.
It seems that Rich's brother, Tom, is an American agent trying to meet a defecting scientist, and the Russians are trying to stop the meeting before it happens.