The title character is introduced immediately with dramatic impact, getting his assignment and then leaping out of the airplane. (Leaving one to wonder just who shut the door after him.)
We get a rare glimpse of Nelson's home-away-from-home (I'm sure that he thinks of the Seaview as his real "home") on the grounds of the Nelson Institute. He's accosted by a stranger who claims to be an Intelligence agent, although of course, being on assignment, he can hardly carry identification with him. He asks Nelson to use his influence to see that George W. Penfield is not confirmed as the new Secretary of State. Nelson is incredulous--Penfield is a well-known and beloved character--but he must have thought twice after he or someone discovered the agent's body outside his home later that night or the next morning. The agent is the first victim of the left-handed man, who's killing gimmick wouldn't be out of place in a James Bond movie.
Following the opening credits, there is a splendid sequence with Captain Crane showing off the Flying Sub to George Penfield. This episode would, in fact, have made an excellent introduction to the Flying Sub, as Crane put it through its paces. Crane, by the way, seemed at several points to be really enjoying Penfield's nervous reactions to some of the maneuvers. We also get the first of a number of scenes in the series starring the comedy team of Sharkey and 'Ski, whose interchanges are purely to provide touches of comic relief.
Back at the Institute, we meet yet another of Nelson's secretaries. (The man must be a tyrant in the office, at the rate he goes through them.) We also meet the person who sent the Intelligence agent to Nelson--Tippy Penfield, daughter of George Penfield. This is where the plot began to slide askew for me. Tippy is not a "political" daughter, she's an airline stewardess (who dresses the part all through the episode), so one wonders how she got in touch with an Intelligence agent in the first place. Her attitude is peculiar, to say the least. She seems quite casual about the fact that her father is not suited for a high political position--you'd think that she'd be a little embarrassed. While interacting with Nelson's secretary, her attitude was one of oh-so-superior amusement, and it continued on while she spoke with Nelson. It was almost as if she was playing a game of "spies"--except that a man had actually died.
Her amusement received a little check when she and Nelson traveled to Los Angeles to pick up the proof about her father. Old Lefty had gotten there first, killed the man on the scene, and was searching for the evidence when Nelson and Tippy showed up. In spite of the chaotic scene which followed, Tippy did have the presence of mind to grab the evidence where it was hidden. (Nelson, on the other hand, pulled what would turn out to be a poisonous needle from the dead man's back and casually shoved it into his pocket. Not a good idea.)
Tippy's proof consists of a home movie she made when she and her father were invited to the home of Noah Grafton, well known (and well-hated) millionaire and Communist sympathizer (which seems like a very odd combination, but then, people can be very illogical). Not only do the two men seem to be on friendly terms, but they have somehow gotten hold of a model of the Flying Sub, which is highly classified material. Nelson is convinced, and, as he warned Tippy, he will now do everything in his power to stop Penfield.
An attempt on his secretary's life provides more proof that things are seriously wrong. Institute security being what it is, Lefty gets away without too much trouble. In the meantime, Tippy has returned, and after praising Nelson for having the courage to openly oppose her father--she asks him to renege. This is another place that doesn't make much sense. Tippy had previously seemed certain that, as her father's daughter, she would be safe from harm, but, as she would confess further on, Grafton changed her mind about that. She's worried about getting killed, yet there she is, safely inside the Institute grounds, with Nelson's offer of security guards, and she walks away.
Nelson goes on board Seaview in order to draw out Lefty. Lefty manages to sneak on board (looking remarkably like Captain Crane as he does so). In spite of knowing beforehand that the man would be trying to come aboard, one man gets killed, and Sharkey nearly does as well--it's just chance that Kowalski happened to spot what was going on.
Nelson, Kowalski, and Lefty get on board a plane, only to discover, too late, that Tippy is there as well. Tippy still seems remarkably casual about the whole situation. They are waylaid to Noah Grafton's estate, and find that Grafton plans to kill Nelson so that his puppet Penfield can continue his work. Penfield, for his part, lives up to Grafton's opinion of him as the "essence of mediocrity"--he and his daughter both stand there as Grafton trashes his character without the slightest protest. It doesn't seem to occur to Lefty that if Nelson's "accidental" death on board the plane is to be feasible, Lefty's body will need to be found there as well. Too bad Nelson didn't bring that up; it would have made for an interesting reaction. Crane and Company of course show up in the nick of time, and, in a scene straight out of "Escape from Venice" start a large fight following the introduction of a smoke bomb. Poor Penfield doesn't even get the chance to die heroically--he's gunned down in seconds. Grafton gets killed accidently by Lefty--which again is straight out of "Venice".
A pretty good episode, all in all, but I think it could have been better.