The episode was directed by Don Leaver and written by Lester Powell.
[2] Steed and Dr. King are assigned a mission to recover a microfilm containing the stolen plans of a missile early warning system.
Shipboard, they meet knives and a drunken film star.
[3] Mission to Montreal is introduces Dr. Martin King (Jon Rolloason), a thinly disguised reworked character of Dr. David Keel, marking the first of three appearances in the series.
The other Keel episodes held over and rewritten for series 2 are The Sell-Out and Dead on Course.