When "Stone, Cold Dead" begins, a man (Dack Rambo) is trying to sexually assault a woman aboard his boat. However, he accidentally kills her in the process and proceeds to toss her and her bicycle overboard to hide the evidence. However, just before this, a credible witness saw this same woman arguing with her fiancé and it is assumed he killed her when her body washes ashore. Cannon investigates the case for some time, but comes up with nothing. His only possible clue is the missing bicycle. So, he dons scuba gear and begins looking...
The plot of this episode is pretty good. But what appealed to me were the scuba sequences. You should note that the diver was way too skinny to be Frank Cannon, however! And, since I am a diver myself, I marveled at how badly the one stuntman dove--flailing his arms about (when you dive, you actually barely use your arms as well). As to all the underwater footage, it was quite good and was like merging "Cannon" with "The Undersea World of Jacques Cousteau"! Also, in case you were wondering, YES, spear guns are THAT inaccurate and the guy missing Cannon (despite the big target had it really been him) wasn't surprising at that distance. Overall, interesting and worth seeing--even if you might find it hard to believe William Conrad in scuba gear!