"Traitor in Zebra" begins with the arrest of Sub-Lieutenant Michael Crane (Danvers Walker), believed to be the traitor who has been leaking missile defense secrets to the enemy, for which he pleads his innocence (the setting is a naval base in Wales). Posing as a psychiatrist, Steed mingles with the other officers, one of whom, Sub-Lieutenant Ken Graham (Willaim Gaunt), is convinced of Crane's innocence, and has written a report of other ways the traitors could have leaked information, throwing the villains into a panic. Fairly routine entry featuring characters that are interchangeable, with John Sharp (later seen in "Murdersville" and "Bizarre") standing out as Rankin, an artist passing on messages by simply walking his dog. Other series veterans include Richard Leech ("Dressed to Kill" and "Murder ... Highly Improbable"), Ian Shand ("The Grandeur That Was Rome"), and Noel Coleman ("Return of the Cybernauts"). As a shop girl whose boredom leads to murder, Katy Wild had a brief career in horror films at the time, appearing in "The Evil of Frankenstein," "Dr. Terror's House of Horrors," and "The Deadly Bees" (this was her only episode). Ending on a personal note, it was 1991 on A&E that I discovered the early AVENGERS episodes with Honor Blackman, and this was the very first time I had seen her as Cathy Gale (now of course I have them all).