A strange alien rock appearing at the home of TDF agent Ishiguro is the first part of a plot to take over the Earth. Soon an alien plant creature stalking the street and turning its victims into plant monsters themselves.
TDF agents are sent to investigate a crashed alien spacecraft, a strange girl appears and leads our heroes on a merry chase, and soon it is revealed to be a plot to steal Dan's Ultra Eye and his ability to transform into Ultraseven.
A new classified ship for the TDF is sent out to investigate the disappearance of several vessels, unfortunately, this results in the "MAX" being captured in an alien tractor beam and taken into space.
An alien spacecraft blasts its way through Earth's space defenses, destroying two fighters in the process, now on Earth the rogue extraterrestrial needs fuel for its marooned spacecraft.
Captain Kurata of the Earth Space Defense Force takes it personally when he loses some of his men to an alien spacecraft that is now hiding in some nearby mountains.
Ultraseven tries to negotiate peace between Earth and the Alien Pedan, unfortunately the treacherous extraterrestrials only have invasion on the minds.
A probe presumed lost three months ago suddenly returns to Earth. The Ultra Guard is sent to investigate only to see the spacecraft explode shortly after landing. A strange stone found by a young boy could be the answer to this mystery.
An earthquake traps a miner who has a connection to Ultraseven, the Ultra Guard is called in due to the suspicion that the earthquake may be of alien nature.
Many ocean-going vessels start disappearing without a trace, with one SOS stating they were being attacked by the long-since sunken battleship Yamato, which sends the Ultra Guard to investigate a possible alien connection.
A sudden cold front turns is the harbinger of a Third Ice Age as TDF headquarters is slowly turned into a deep freeze by a nasty cold breathing monster.
The Terrestrial Defense Force develops a new super-weapon that can destroy a whole planet and when it is tested against a supposedly uninhabited planet Earth soon finds itself facing a very angry space monster.
A professor at a local university is discovered to be an alien spy whose new satellite could reveal the Earth's weakness in advance of an alien invasion.
An approaching asteroid turns out to be a strange floating island that emits magnetic jamming waves, ones that not only prevent Ultra Hawks from flying but also stops Dan from turning into Ultraseven.
Two ships of the Ultra Guard are sent to investigate an explosion at a TDF moon base. One of the Ultra Guard members secretly works against his teammates with a strange telekinetic device.
Aliens target the top scientists behind an artificial sun project, a hypnotized TDF agent is a pawn in the alien's plan to assassinate the head scientist.
A young woman steals Dan's Ultra Eye while he is out on patrol, this is the first part of an alien plan to destroy the Earth with an interplanetary missile.
A young boy refuses to give consent for his much needed heart surgery unless Dan of the Ultra Guard attends, unfortunately a giant car eating robot keeps Dan rather busy.
A race of undersea beings claim to be the "rightful rulers" of the undersea floor, having been driven into the sea by humans eons ago, and now they will fight back against human's further expansion into the sea.
An alien invasion uses a "Boy Who Cried Wolf" tactic to discredit amateur astronomers so that Ultra Guard will ignore them and thus allow the alien fleet to sneak in undetected.
A man stumbles home drunk one night only to find his wife, kid and neighbors all claiming that they don't know who he is. Dan and Furuhashi investigate and soon discover an alien invasion plot housed in the man's apartment complex.
The numerous fights with alien kaiju have finally taken their toll on Dan/Ultraseven as he finds himself sick and weak, his superior demands he return to the Land of Light to recuperate but he refuses as Earth still needs him.
With Dan/Ultraseven weakened and possibly dying the alien invaders ramp up their plan to conquer the Earth. If mankind doesn't surrender billions will die in "The Biggest Invasion in History."