A frequently used ploy in this series is the idea of deterrent weaponry. Those oceans seemed to be packed with various missiles whose primary purpose is to make the enemy think twice before starting anything. Given the number of times someone has tried to turn the deterrents against them, you'd think they'd have given it up as a bad job by now.
The deterrent in this case is a whole fleet of armed, drone submarines, designed and built three years previously by Admiral Nelson and Admiral Halder, who is a citizen of some unnamed, "Eastern" country. While conducting what is presumably a routine check on these drones, they are startled (to say the least) when it unexpectedly arms itself and takes off, firing three missiles at the vicinity of New York City. The Seaview's quick reactions manage to intercept and destroy two of the missiles, but the third is only winged. It misses its set target, but still causes three deaths and a great deal of damage. (Admiral Johnson had indicated that his people would try to knock down any missiles that Seaview missed, but there's no indication that they tried very hard.)
Enter Senator Kimberly, a loud, obnoxious political animal who "knew all along" that the drone sub program was a mistake. Nelson more or less allows the man's ranting to slide off, and addresses himself to the problem, calling on Admiral Halder for assistance.
Halder and Nelson seem to share the same taste in laboratories. Perhaps they used the same decorator. The moment Halder breaks contact with Nelson, we find that he, in fact, is the source of the problem. I was disappointed that they didn't keep the audience guessing a while longer, but I suppose they wanted to give Roger C. Carmel the fullest chance to strut his stuff. He heads to the Seaview, accompanied by a lady captain (last seen snuggling on a beach with Lee Crane.)
Crane had indicated that the self-destruct device on the drones had a radius of five miles, so presumably, when they sent divers to get into the drone, they then retreated a proper distance. Captain Tabor stealthily notifies Halder's base that the men are approaching the drone (with no one noticing this radio contact from inside the Seaview). The destruct sequence is activated. Admiral Halder, with supreme understatement, acknowledges that they have a serious problem.
Seeing Nelson's determination to locate the "tell-tail" of the drone, Halder returns to his his base, leaving Tabor behind to provide distractions. (No, not that kind of distraction.) She does so via coded tapes that she gives to Sparks (who gets a fairly sizeable role for a change). The codes cause more drones to "defect" and head for the East Coast of the United States.
Nelson gives up the search for the first tell-tail, instead deciding to retrieve one from a live drone. Crane's job in this case will be just as difficult: maintaining a force field in the vicinity of the drone to prevent its self-destruct from activating. Foiled from sending another coded message, Tabor tries direct sabotage of the Seaview. Only the crew's quick reactions (and long familiarity with lurching submarines) enable them to keep the force field in place. Oddly, Crane does not send anyone to check on the source of the internal problem.
Nelson fetches the tell-tail, but it's going to take a long time to decipher it. Nelson decides to take it to Halder's lab to have it done more quickly. On his arrival, Halder blithely informs him that he has been the one directing the drones, giving us the treat of seeing Nelson attack a man nearly double his size. Makes a pretty good showing, too. Halder indicates that it is not his government who is attacking the U.S, but Halder's own small group of revolutionaries. He also, quite casually, tells Nelson that he's prepared to attack his own country as well, if they don't fall in with his demands.
Sparks, whose suspicions have been aroused by the odd-sounding tapes Tabor had given him, records the messages and slows them down considerably, finding that there is indeed a code hidden in them. They don't actually say that the code has been cracked, but anyone familiar with Crane will notice that something's up just in the way that he speaks with Halder and Captain Tabor. On Halder's request that Tabor be sent back, Crane courteously offers to bring her himself.
Up to this point, Halder, when dealing with the Americans, has maintained a quite jolly, albeit superior, attitude. This vanishes in an instant when Crane calls him a traitor, and you can see the savagery underneath. Crane, for his part, holds an expression of icy contempt that never wavers, even when he's struck.
This next scene is one of my personal favorites from the series--just one of those little things. I'm sure everyone has one. Tossed into the narrow little storage closet with Nelson, Crane regains his balance, peers over his shoulder at Nelson, and says, "Well, I'm glad you're here." Nelson, who undoubtedly has been praying that Crane and Seaview will discover what's been going on, says with barely suppressed wrath, "You are?" Crane, with devastating simplicity, answers, "If you weren't here, you'd be down at sea. This is better." I don't know why this exchange tickles my fancy--it just does. Crane quickly appeases Nelson by showing that his jacket is packed with equipment that would do James Bond's Q branch proud, and they instantly set about escaping the closet and dealing with the drones. Luckily for them, the relevant room in the base is right next door.
Admiral Halder obviously knows Nelson very well. Informed that one of his drones has suddenly veered off course and is coming straight at them, Halder instantly knows that his "guests" have something to do with it. After a few brisk exchanges with the enemy (the fight scenes are well done, the stunt men blend in pretty well) Nelson and Crane get back to the Flying Sub and take off, just in time, naturally.
I found it rather amusing at the end, when Nelson discussed the situation with Admiral Johnson. The obnoxious Senator Kimberly contrived to be absent at this point, probably to avoid having to make an apology.