. Seaview is under polar ice, trying to discover the cause of increased flooding around the world. Living dinosaurs? The glass is shattered, killing him. An alien plant takes over Admiral Nelson in a plan to turn the Seaview into a giant greenhouse where it can take over the world. Snow has struck the United States as far south as Florida, and Nelson knows why: somehow, the Gulf Stream has shifted east, permitting colder temperatures. When Admiral Nelson hears of this he is fascinated by it and takes the Seaview to the Norway to investigate and interview the one survivor. The Seaview is sent on a mission that will take into to some of the most dangerous waters in the world for submarines. Van Wyck is in reality the first mate who killed the Captain. Seaview has been sent to the ocean floor by mysterious pressure impacts. Will the country in question survive the machinations of the evil man who wants to take over?

Two Soviet scientists come aboard Seaview to carry out the work -- but one of them is an imposter. . Injured in a fall, the President of the United States is in desperate need of surgery -- and the operation must be kept secret. Nelson and Crane have their hands full trying to protect the President of the United States (a guest of a Middle Eastern Shah on a nearby yacht), and regain control of their ship.

Dr. Turner (Victor Jory) is aboard to stop the eruptions.

While racing to help a foundering research vessel, the Seaview's nuclear reactor goes critical. Join the crew of the Seaview aboard their super high-tech submarine, where no mission is too dangerous and no threat is too deadly, be it enemy agents, mad scientists, deadly sea creatures, or impending nuclear disaster. The Seaview crew is being entertained by puppet cairactures of the Captain and Admiral, compliments of Professor Multiple. A space probe returns to earth and is recovered by Seaview...only to unleash an alien organism aboard. The evil twin is out to create a radioactive "plant man.". Only Nelson and Crane avoid capture and transformation. Trusting no one, Nelson loses his grip on reality, arresting Doc, fighting with Sharkey and finally launching a nuclear missle at the fleet!

Admiral Nelson takes Morton and Sharkey into his confidence. But even Anna is not all she seems.

They discover the cause is a magnetic beam of immense power. Although treated in Sickbay with a special anti-radiation device, the Captain does not come out of his coma-like state. Seaview rescues two men adrift at sea, only to discover they are escaped prisoners intent on not returning to prison. A mysterious cloud is enveloping the Earth and causing massive Tsunami and other catastrophic environmental damage. Credits, trivia & commentary- Mark Phillips. (Apparently, Doc hasn't read the script.) The extremely well-guarded source... A very important Soviet official is defecting to the USA with his daughter. A mysterious weapon is destroying American U2s. The Seaview investigates why part of the Italian coast has become overrun with jungle growth. Such fanciful ideas must surely be the ravings of a madman. The Admiral has built a device that might help, but first he and Crane have to fight their way through the overgrown corridors to prevent the missiles being used to spread the infestation even farther. When Crane tests a new atmosphere to deal with extreme pressures, he turns into a Man Beast. One dies, and the survivor is infected by a virus that causes him to change from man to werewolf and back again. Can the crew stop this invasion before these amphibian aliens take of the Earth? Bainbridge Wells is filming a segment of his "Science On The Move" television series on a small island off the coast of Chile. An explosion renders him unconscious. Meanwhile, on Seaview, Major Amadi demands asylum. . The Seaview is dispatched for damage control. A man named Alpha from 2823 sends 2 Collectors to bring Nelson to his time to add the Admiral to his collection of military officers. A research vessel vanishes during a routine mission near an island off Greece. Thanks to the hard work of some enemy agents aboard, Seaview seems unable to rescue the Captain. Nelson suspects he wants to lead Seaview to a watery grave. Nelson disagrees and takes Weber and two others aboard Seaview to decide the course of action as the sub races to the firing point. Accompanying them is Dr. Turner who's suppose to help them. Will Nelson's rescue mission succeed? Fortunately, a mysterious sailor, Old John, appears along their way and helps the young prince. Crewman Patterson has a special interest in the mission. Multiple remains on-board when the sub departs, and his dolls soon come to life, replacing their real-life counterparts. In blizzard-wracked Florida, Nelson contacts a meteorologist who may be able to help explain the strange weather conditions. Mr.Pem returns to help Admiral Nelson prevent the Seaview from exploding. Asian powers attempt to interfere with the American Space Program. At the same time a skirmish in the control room of the Seaview sails directly into a derelict mine field.

Admiral Nelson becomes involved in a project to develop an amphibian adaption for man. * Footage of Morton and Kowalski trapped in an underwater cave was borrowed from previous episodes. Captain Gantt, an ego-maniacal scientist, is in a nuclear sub testing a powerful new fuel. A series of strange events leads Nelson to believe there may be a way for a submarine to enter the Loch. Evil forces seek to destroy Nelson before he implements his plan -- in the chaos following the tidal wave, they hope to take over the world! Meanwhile, Seaview is sailing in circles, and the visiting Commander Van Wyck seems to have disappeared. The pirate 'drafts' Kowalski, who makes a very convincing and quite blood-thirsty buccaneer. The assassination of a king means Prince Ang receives an early promotion. Nelson is to meet a scientist working on a secret project at Loch Ness. Admiral Nelson is kidnapped from a plane during mid-flight and held on a remote island by Nazis who plan to conquer the world.
Can Crane recover and return to the Seaview before Nelson can destroy it? Commander Morton Crane, the only person aboard the sub, realizes he may not be as alone as he thought. An undersea earthquake exhumes hundreds of strange metallic capsules, and a powerful humanoid creature who could destroy mankind is restored to life after millions of years in suspended animation. In exactly eleven days there will be a terrible polar earthquake. With the official recovering in the sick bay, the Seaview now must either leave the daughter behind or make a rescue attempt. * The white furry monster costume also appears in at least one Lost in Space episode. Help arrives in the form of a mysterious flute-playing old man who befriends the boy after he is picked up at sea.

Again. While inspecting undersea bomb shelters with the President, aides attempt a power grab. The ghost of Blackbeard is alive and well, and he wants the Seaview and her crew. He is taken prisoner and nearly loses his life. But it is later revealed that his puppets are alive and they plan to take over the sub. (There actually is a Lincoln High in Coney Island.) Nelson and Crane are met with hostility from the locals and find the survivor has died. . The Seaview is seized by a man calling himself the "Buccaneer. Episode synopses-Mike Bailey. The series first aired on September 14, 1964. The Captain is soon captured and severely beaten. Dr. Alex Holden is hunting a gigantic whale in which he has injected an experimental growth serum.
Lt. Now Nelson has to stop Pem's far-reaching plan to take over the world and avoid the explosive disentergration of Seaview.

They must put Crane to the test to find out whether or not he's the man they know. It seems that after they had left a mysterious island, the men became deadly enemies. . Then they discover that the beam is powerful enough to seize all the metal objects aboard Seaview herself, and begin dragging her relentlessly to her destruction. A Soviet satellite has crashed into the sea and its nuclear reactor must be disarmed before it causes a disaster. In fact, he has a lot to learn about everything.