This episode of "Cannon" ("The Seventh Grave") features several familiar guest stars--Barry Nelson, Jim Davis and a young Shelly Duvall. It's a very unusual show for 1973 because it's about a serial killer who is targeting young girls. In this sense, it's pretty unusual because TV shows really didn't have the fascination with serial killers yet. However, as far as the show goes, it's only okay. I would have scored it a 7 but the big fight at the end made no sense. I had to actually stop the DVD and rewind and watch it again...and it still made no sense. Cannon was fighting it out with the killer and the killer was about to kill Cannon...and then just falls down and is unconscious! Huh?! A very poor ending to an otherwise decent episode. See the final scene and you'll see what I mean.