AllMovie

Steed and Emma are put on the case when the body of an agent -- four inches taller than he was in life -- is discovered. Their investigation leads to Castle De'ath, a formidable (and, reportedly, haunted) Scottish castle. While Emma poses as a woman determined to transform the castle into a tourist attraction, Steed explores the dank and musty cellars of the fortress and stumbles upon a secret submarine base. Written by John Lucarotti, "Castle De'ath" was originally telecast in England on October 30, 1965; it was subsequently aired in the U.S. on May 2, 1966.