At first glimpse, it would seem as though Apple One has been sent out, but it turns out to be a drag net for routine specimen collecting. (Routine for them, perhaps, but not the viewers.) They're bringing up something fairly bulky, that shifts around in the net. In the meantime, Nelson and Sharkey are out in the Flying Sub, searching for an uncharted island. This was an irritating point, because we're never informed as to how they learned of the existance of this alleged island.
The specimen is brought on board, and Kowalski identifies it as an egg, presumably by virtue of its shape--it's six feet long, a trifle bigger than the average egg. Crane orders a guard posted until Nelson can take a look at it. Chip Morton orders them not to touch it--an order that Crewman Ray flat out ignores. Kowalski takes up position outside in the corridor, while Ray is left inside to tidy up the place. Moments later, the egg splits, and a man-sized pinkish biped emerges. Its skin has a pebbly appearance, with odd flaps here and there. The eyes look pretty cool, but the mouth is set into a permanent sulk. It's also incredibly savage--fresh out of the egg, it immediately grabs Ray and throttles him. This was even more shocking than seeing Ron tossed overboard in "The Mermaid"--Ron was using a different name, and he turned up again by the end of the episode--but Ray is best known as Ray, and it was harrowing to see him die. Hearing some noises, Kowalski goes inside--and is equally stunned at seeing his friend lying there. He shows more reaction than is normally seen for a crewman's death. The pink thing comes out of hiding, groaning and making clicking noises, and tosses Kowalski around like a beach ball before lumbering out into the corridor. It walks very awkwardly. I don't know if that was the director's orders, or if the rubber suit was simply too tight to allow natural movement.
The Flying Sub returns, and after sending Sharkey to run their collected information through the computer, Nelson immediately heads for the Missile Room to examine the egg. The first thing they see is Ray's body--and again, the reaction to a crewman's death is more than the usual perfunctory remorse. A groggy Kowalski, helped up by Crane, calls Ray's name in an anguished tone, and Crane gives him a consoling pat on the back. After 'Ski tells them what occurred, Nelson calls for security measures, and orders the men armed with tranquilizer or stun guns. (I had always thought that stun guns WERE tranquilizer guns.) Kowalski is sent off to Sickbay; he leaves slowly, still staring over at Ray, as are Crane and Nelson.
Nelson wants to find the breeding grounds, and thinks that the unknown island may be involved. We learn that there have been four reports of a "giant amphibian" being spotted over the course of five weeks. The four sightings form a square on the map, and their own specimen was found more or less in the center--just where the uncharted island is rumored to be. (There is still no explanation of how they extrapolated an island out of these sightings.)
The creature shows up at the Reactor Room, where Patterson is checking panels. Patterson, spotting it, grabs for the microphone. Oddly, he acts as though he's heard nothing of the security measures--he reports "a" creature, not "the" creature. Patterson, unflappable as usual, sounds quite steady as he reports that the creature is entering the room. It's Chip Morton who sounds urgent as he tells Patterson to get out of there--the thing is a killer. Patterson manages to get the hatch unfastened before the creature throws him. (Throwing seems to be the favored technique.) Two security men shoot at it, but get knocked down and out. The creature appears momentarily as though it's reacting to the shots, but once out in the corridor, it lumbers steadily off. Patterson reports the situation, and Chip orders everyone but security cleared from the area. At this point, Crane and Kowalski head off in the FS1 for another attempt at finding the island. Nelson states that if the island is the breeding ground, they'll have to destroy it. (Nelson's scientific curiosity seems to have gone by the wayside.)
Crane and Kowalski are having no better luck finding the place. Crane swerves to the south, and Kowalski suddenly spots the island--right where they had been before. Crane reports to Seaview, where they are still searching for the creature. (You wouldn't think it would be that hard to locate such a awkwardly moving thing, but, well, that's Seaview Security for you.) As Crane moves them in for a closer look, they're suddenly grabbed by something and yanked down into the water. Kowalski makes some comment about being at a dangerous depth, which is ridiculous. They end up at 1,200 feet and we've seen FS1 at considerably lower depths. There's the usual blowing out of various panels, and, of course, the radio is dead. Starting to check on the damage, they hear a strange sound--then suddenly freeze. The diving hatch opens, and another pink creature--looking perfectly dry--enters. The pebbly texture on this one is darker than on the hatchling--presumably a sign of age. A cluster of dark spots over the mouth give the impression of a mustache. This creature also moves very awkwardly. Perhaps it's a reaction to being in the Earth's environment, but it just doesn't seem right that a species would have such difficulty in movement. Unfreezing the men with a wave of its hand (the usual method with aliens) it speaks. (Jon Abbott, author of IRWIN ALLEN PRODUCTIONS, comments that all these aliens tend to sound like news anchors.) The sulking mouth doesn't move much. It states that it has "no intention of harming YOU." The emphasis on "you" makes it sound as though it has intentions of harming others, though. It plans to take the men to the island. Crane protests, drawing his gun. The creature freezes them again--and then, all of them vanish. They reappear shortly afterwards on a beach. The creature disarms both the men before unfreezing them. Crane and Kowalski are considerably jolted at the sudden change of view. The creature announces that he is from Scorpius. He's been on Earth for a long time, and has learned many languages. He tells them that it is foolish to resist (the old-fashioned version of "Resistance is Futile") but naturally Crane and Kowalski try it anyway, and promptly get frozen again.
Meanwhile, back on the Seaview...Nelson had set guards and secured the Manuevering Room, having the controls set on automatic before sending the crewmen away. The hatchling comes up to the room and takes out the guards in a matter of moments before going inside. Another crewman turns up, alone and unarmed. (If he's Security, he should have been armed; if he's ordinary crew, he shouldn't have been there at all.) Picking up a fallen gun, he goes into the Manuevering Room and shoots at the creature. Lousy shot--he inflicts considerable damage to the panels, but the creature seems unaffected until it backs into the panels. The Seaview lurches considerably, knocking out the crewman with the gun, and the creature itself falls to the floor. Up in the Control Room, they find that Circuitry, Engineering and Manuevering have all shorted out. They have no control of planes or rudder, and the propulsion unit is nonfunctional. (Just another routine day on the Seaview....) Nelson goes alone (!) to Manuevering, and finds the three men--but not the creature, who seems to have recovered quickly. Nelson reports three casualties, but it isn't clear if they are dead or not. The implication is that they're dead, but if the third crewman is, that would be the first fatality of a Seaview lurch.
Crane and Kowalski have been taken inside a cave, filled with equipment and one or two more aliens. The leader is messing around with something that will turn out to be a moniter screen. He shows the men a view of a shoreline, crowded with eggs. (Kowalski says that there are millions--he must have seen a lot more than I did.) The leader explains that their eggs hatch full grown members of their race. (Either those eggs must grow somewhat after they're laid, or else Scorpian womenfolk must be huge!) The egg found by the Seaview had been torn loose by some turbulence. (Presumably this explains the other four sightings, as well, but it's never mentioned.) Being on Earth apparently slows down the maturing progress considerably--the hatchery has been there for centuries. The leader seems to be somewhat ignorant of his own species' facts of reproduction--he has only just learned that low level radiation--as found in the Seaview's reactors--speeds up the hatching process. With the reactor, he can hatch out all his millions of eggs overnight. (Actually, the hatching on the Seaview only seemed to take a few minutes.) They will then take over the Earth--as they've taken over other planets. (I wonder if the leader has gotten messages from home, asking what's taking him so long on Earth.) Crane angrily states that he's not gotten the Seaview yet--but the leader smugly states that it's only a matter of minutes.
The hatchling comes to the Control Room. Sharkey is the first to spot it. He and Chip dither about what method to use to deal with it. They hear an odd clicking noise, which doesn't seem to be coming from the creature; perhaps it's a transmission from the island. This might explain why the entire Control Room crew froze without any motion from the hatchling--although it did motion to make them vanish. Perhaps the leader was responsible for the freezing. The hatchling starts looking around the Control Room. He plays with the controls--setting off yet another lurch, which clues Nelson in that something's wrong. No one answers from the Control Room. Nelson is joined by Patterson, who also cannot raise anyone. They head for the Control Room. Walking towards the hatchling, Nelson bangs his head (really nice reaction!) into a force field. They quickly exit the room. The hatchling appears to guess that they're going to return by the circular stairs, and goes off to hide. So why didn't it just freeze Nelson and Patterson when it had the chance?
Back in the cave, the implication is that they've been watching the hatchling's activities on the screen. The leader tells Crane and Kowalski that, after the hatchling learns how the Seaview works, it will destroy it. They will then retrieve the reactor. The leader seems quite confident that the reactor itself will not be harmed. Nelson and Patterson return, Nelson armed with a laser pistol--which is probably the most "sci-fi" looking piece of equipment I've seen on board. The hatchling grabs Nelson, Patterson grabs the hatchling, Nelson shoots the hatchling, which disappears in an explosion. Boy, that was quick. The Control Room crew reappears, understandably confused. Nelson doesn't have time for much explaining--they need to get back underway.
Time for Scorpian Plan B. The leader asks Crane if he would like to return to the Seaview. Crane is, quite sensibly, suspicious. The leader seems unhappy with his mistrust--he has only the best intentions toward them. This scene was rather ridiculous. Why did he bother even trying to lie to Crane, when Crane knows perfectly well what his intentions are? Crane and Kowalski are, for the moment, completely helpless--as proved when they make another escape attempt, which lasts all of ten seconds or so. Trying to make them believe that the aliens will actually send them home seems to be just an exercise in sadism. They are led to FS1, which has been moved from the seabed. The leader mentions that they have the ability to move heavy objects, which seems like quite an understatement--the FS1 has been jammed into a rock face, and the whole front of the hull has been removed. Crane and Kowalski make it plain that they're not going to cooperate--so the leader freezes them and has them set in the pilots' chairs.
Back on Seaview, repairs are under way. Sonar picks up an object 5,000 yards away. It looks like the FS1, but it's moving in a straight line, like a torpedo. Calling on the radio gets no response. Nelson orders torpedos prepared, to Chip's horror. The sail camera shows the FS1 approaching, but Nelson doesn't belay his order. Magnification shows Crane and Kowalski inside, looking blank-faced. Nelson immediately orders the torpedoes launched--sending the order himself when Chip hesitates. The explosion causes another major lurch (that'll set back the repairs). Chip is outraged--and rather obtuse--it takes Nelson a while to spell it out to him that they had seen an illusion. Something is attacking them--presumably related to the alien they had had on board.
Nelson, as usual, is proving more difficult to handle than expected. The leader will now have to come up with a Plan C. He will bring the Seaview to the island (if his people can shift large objects about, why not just pick up Seaview and plant it on the island?) In the meantime, he cages Crane and Kowalski in the remains of the FS1 with a force field. (Hedison and Monroe should have practiced their pantomime a bit more--the placement of their hands as they explored the force field made it look very uneven.)
As Nelson is looking through the periscope, the island abruptly appears, which convinces Nelson that it's not an illusion. The leader operates a switch, and the Seaview is suddenly being dragged towards the island. Nelson orders missiles prepared--even though he's certain that Crane and Kowalski are there on the island. Chip is the one who gets to spell this out the audience this time around. Inside the force field, Crane discovers that the aliens had overlooked the laser pistols stored on board. Crane speculates that the aliens are so far beyond things like hand weapons that they didn't recognize them--but the leader had disarmed them previously. I think it's more likely that they complacently ignored the pistols--or perhaps didn't even look. The leader also seems to have ignored the possibility of the Seaview firing on his island. Crane and Kowalski shoot the force field--which literally "breaks" with a shattering sound.
The Seaview is pulled into shallow water. Nelson tries to hasten the firing of the missiles, but before they can power up properly, they run aground, causing still more damage--especially to the firing mechanism. Back in the cave, Crane shoots the control panel before the leader can destroy the Seaview. The leader, who up to this point has spoken with a smug, superior tone, suddenly sounds like any angry villain as he bellows his outrage at having been thwarted. Crane and Kowalski shoot him before he can wave his hand and kill them. Back on the Seaview, Sharkey eyes the damaged firing panel with dismay as Nelson's frantic orders to fire come over the intercom. Pulling on gloves, he has a crewman press on the firing button while he jams the firing cable back into place. The island goes up in a burst of flame. They now have time to consider their missing crewmates. Just as Nelson angrily snaps at Chip that they have no time to try and search for them, they hear a sound from above. Crane and Kowalski, drenched and breathless, drop down the ladder. Having spotted the Seaview from shore, they swam out to it (probably breaking Olympic records as they did so) and reached her just as the missiles hit. The frantic pace of the episode comes to an end. Crane and Kowalski cheerfully head off to get dry clothes, the relieved crew happily sets about repairs again...but Nelson, oddly, is left grimly staring off into the distance, leaving you wondering what he's thinking about.