During his research, Henry Pym discovers a serum that allows him to shrink his body to the size of an ant. After venturing outside and confronting hostile insects, Pym decides that his findings are too dangerous for mankind so he discards the formula.
Realizing that his research on size reduction should not go to waste, Henry Pym starts studying the ants and finds a way to communicate with them using a specially made helmet. He designs a protective costume made of unstable molecules and becomes the Ant-Man. He puts his abilities to the test as he fights off communists who came to steal an anti-radiation formula that he invented.
Henry Pym builds a catapult in a miniature secret room inside his lab to rocket him to specific locations in the city. He uses it for the first time when Comrade X comes to New York to steal his shrinking formula.
Ant-Man is warned by his ants that a robbery is going to occur in a museum and that it is a trap set by Egghead, whom he faces for the first time. Having prepared to counter-attack, Ant-Man captures all the mobsters except Egghead who manages to get away.
Henry recalls how his wife Maria was killed during their honeymoon in Hungary and why he chose never to take wife again. Shortly after a visit from renowned scientist Vernon van Dyne and his Janet, the girl calls Pym to announce that her father has been killed, most likely by an alien. Seeing her determination to find the murderer, Pym reveals his identity and takes her as partner. Calling her the Wasp, he gives her the power to shrink size and grow wings when she is wasp size. When the creature from Kosmos attacks the city, they engage on their first mission together. With the information provided by the ants, they are able to destroy the alien.
The Fantastic Four and Ant-Man use Pym's shrinking serum to enter a Micro-World where Princess Pearla was overthrown by the tyranny of Doctor Doom. They manage to defeat the villain and free the Micro-World people. After the villain has fled, Ant-Man and the Fantastic Four use Doom's enlarging ray to go back to their world.
Ant-Man and the Wasp intercept a message from the Teen Brigade asking for help to locate the Hulk. After meeting the teenagers, they join Iron Man and Thor to track down the green menace. When the others have located the Hulk and try to stop him, Thor arrives with Loki who confesses that he framed the Hulk to set a trap for Thor. With the capture of the God of Mischief, the four heroes and the Hulk decide to form a team called the Avengers.
In honor of the memory of Janet van Dyne, Hank takes on the mantle of the Wasp
Hank Pym has invented a new formula that enables him to grow in size, up a limit of twelve feet where he can no longer support his own weight. He has also made his formulas into swallowable capsules and changed his name to Giant-Man. Using these upgrades, he and the Wasp defeat the Living Eraser and bring back scientists who recently disappeared.
Outmaneuvered by a new foe called the Human Top, Giant-Man realizes that his huge size can become a handicap. Despite his efforts to improve his speed, he is still unable to stop the thief. Trying a different approach, he catches the Human Top by getting the authorities to fence all exit points in the neighborhood.
The Avengers discover the body of the legendary Captain America adrift in the sea and take him aboard their sub. After waking up, Cap tells them what happened during the last minutes of his life twenty years ago. The Avengers are turned into statues in New York Harbor and brought back to normal by an alien captured by Captain America and Rick Jones. They agree to help the D'Bari recover his spaceship at the bottom of the ocean. After they resist an attack from Namor, Captain America accepts to join the Avengers.
Hank has bought an engagement ring and intends to ask Janet to marry him. But when his love interest announces that she is going to a party and that the host is probably going to propose to her, Hank painfully concludes that he is out of his league and decides not to go further with that plan. Still, after he rescues her from the Magician, she tells him that there can be nobody else than him.
Still on the trail of the Hulk, the Avengers find clues of his presence in New Mexico. But their former teammate is now in New York City and has defeated the Fantastic Four. They travel back home where they face the Hulk. Soon, the Fantastic Four have regrouped and join them in the fight, but since they never fought side-by-side, they only get in each other's way. Realizing this, they decide to collaborate and finally manage to defeat the Hulk who disappears into the Hudson River.
Baron Zemo assembles a team composed of the Black Knight, the Melter, the Radioactive Man and himself to battle their respective nemesis in the Avengers. But the heroes defeat the Masters of Evil by switching enemies to destabilize them. The villains are arrested but Baron Zemo manages to escape.
Hank Pym discovers a way to cybernetically control size-changing for himself and the Wasp instead of using his capsules. They test it for the first time by defeating the mighty Colossus in Africa.
Learning that his old friend Lee Kearns has been captured by the Communists, Hank finally tells Janet about the death of his wife Maria and why he is always reluctant to get involved emotionally and unwilling to put her in danger.
The Avengers are asked by the Pentagon to deal with the threat of Kang the Conqueror who came from the future to claim Earth for himself. After explaining his origin, Kang is attacked by the Avengers but he easily confines the male members of the team inside his ship. They are freed by the Teen Brigade and the Wasp soon arrives with a weapon with which Giant-Man destroys Kang's suit which controls his weapons. Defeated when Thor uses his hammer to hurl radiation back at him, the Conqueror is forced to flee in his ship.
The Avengers meet Wonder Man for the first time as he helps them fight the Masters of Evil. Then the Avengers discover this is all a set up to lure them to South America where they all get captured by the villains. Ultimately, Wonder Man redeems himself and sacrifices his life when he saves the heroes from Zemo who is about to kill them.
Through training, Giant-Man has found a more efficient way to travel around town by quickly changing to giant or ant size. Using this new skill, he and the Wasp help the police catch and unmask a protection racket gangster called the Wrecker.
Hank finds a note telling him that Janet decided to take a break from him after he angrily snapped at her. Warned by ants that she is in danger, Giant-Man rescues Janet who was captured by Attuma and his Atlantean army. On the way home, Hank apologizes for his rash behavior and she replies that she could not really leave him anyway.
When Immortus captures Rick Jones, each Avenger must confront a legendary figure to free him and Giant-Man beats Goliath. Before all his champions are defeated, Immortus leaves with Captain America. Meanwhile, the Masters of Evil attack the Avengers and gain the upper hand until Cap returns victorious with Rick. The Enchantress casts a spell to bring her team back to the moment before they met Immortus, so for anybody else, it is as if nothing ever happened.
Led by Thor's hammer which has detected evil impulses in the Balkans, the Avengers engage in a fight against the X-Men. Professor X explains that Earth would be in peril if their foe Lucifer was to be slain and convinces them that they will handle the situation.
Ant-Man unmasks a protection racketeer known as the Protector.
Ant-Man saves the human race from the threat of an insect who mutated into the Scarlet Beetle due to radiation.
Ant-Man deals with the Hijacker who has been targeting the armored truck industries.
Ant-Man seeks out and brings back a group of scientists who have been abducted by an extra-dimensional tyrant named Kulla who wanted to force them to build a weapon that would ensure his domination over his world.
Ant-Man defeats a man calling himself the Voice because of his newfound ability to control people by speaking to them.
Ant-Man puts a stop to the Time Master who has invented a device that can age any living organism.
Ant-Man rescues the Wasp who has been captured by Egghead and his minions.
Ant-Man and the Wasp fight off aliens from A-Chiltar III who came to invade Earth, and neutralize their robot Cyclops who has been terrorizing the Greek islands.
Ant-Man and the Wasp have to stop a trumpetist who has learned how to hypnotize people through his instrument and uses that ability to rob banks.
A man with a suit consisting of micro quills and calling himself the Porcupine starts robbing banks so Ant-Man and the Wasp decide to stop his crime spree.
The Avengers meet an alien invader called the Space Phantom who uses his ability to borrow the body of any mortal to put the Avengers against each other, paving the way for his people to invade the Earth. The threat is over when the alien trying to take the immortal Thor's body and ends up in limbo himself. The Hulk announces to them that he is leaving the team.
Learning from their ants that Thor is rampaging through New York, Giant-Man and the Wasp take Iron Man with them to try to calm him down, but he just wants to be left alone.
Rick Jones informs the Avengers that he found the Hulk back in New Mexico. They confront him in the desert to reason with him but it turns in to a fight and the Hulk chooses to escape. Days after, he has found an ally in the Sub-Mariner and they challenge the Avengers to battle them at Gibraltar. When the Hulk apparently deserts in the middle of the fight, Namor plays it safe and swims away.
Months after arresting Nathan Garrett for treason, Giant-Man deals again with the villain who now calls himself the Black Knight and rides a winged horse. They engage in air combat, but the villain escapes.
Giant-Man and the Wasp face the Porcupine who intends to get his revenge but ends up shrinking almost to nothingness after swallowing the wrong type of size-changing capsules.
The Wasp tells Henry the tale of a conqueror who got defeated by the colossal statue he built to intimidate rebels.
Giant-Man and the Wasp are sent by Washington to Santa Rico where they overthrow the tyrant El Toro who won his elections by foul means.
Giant-Man and the Wasp recapture the Human Top who has broken out of jail.
The Wasp's tale about aliens who can turn lead into gold inspires Henry to make some research on such a formula.
The Wasp tricks her partner into taking her to dinner by challenging him with a riddle he is unable to solve.
In New Mexico, the Avengers are attacked by the Lava Men who have been pushing an ever-growing rock outside of their subterranean domain. Thor learns that trying to make it explode would destroy both their races. When the Hulk suddenly appears and engages battle, the Avengers solve all their problems when Giant-Man and the Wasp trick him into smashing the rock at a vulnerable spot, causing it to implode.
Realizing that someone has tricked them to fight each other, Giant-Man and the Wasp join forces with Spider-Man to capture Egghead while he is robbing a bank.
Hank does not believe the Wasp who tells him she arrested her first villain all by herself.
After an Avengers meeting, Giant-Man and the Wasp leave to get something to eat.
Hank warns Janet that the Magician has escaped from prison, but the Wasps captures him all by herself.
The Avengers try to get in touch with Iron Man so he can handle a new menace while they are on another case, but they are told that he is on vacation.
While Iron Man is suspended from the Avengers and Cap is abroad hunting Baron Zemo, Giant-Man and the Wasp are attacked by Thor who has been put under a spell by the Enchantress. After Iron Man has put an end to the spell, the Avengers reassemble to defeat the new Masters of Evil whom Thor sends into a space warp.
Giant -Man and the Wasp seek the Hulk to convince him to rejoin the Avengers but unknown to them, the Human Top has tricked him into fighting them. The Wasp warns her partner of nuclear missile approaching the deserted town in which he and the Hulk are battling, but ultimately, the Hulk redirects the projectile towards another target to save them both.
Iron Man, Giant-Man and the Wasp offer their help to Thor who seems to fly to battle, but the Asgardian prefers to handle his personal matter by himself.
Tipped off by the ants, Giant-Man and the Wasp expose that the Chameleon has set Captain America and Iron Man against each other.
Giant-Man and the Wasp have caught a gang of criminals near the waterfront.
Giant-Man and his fellows Avengers go to a charity event outside New York.
As the Avengers are about to investigate the sinking of entire city blocks into the ground, the Fantastic Four inform them that this is the Mole Man's doing so they prefer to handle the situation themselves.
The Wasp convinces Giant-Man to accept an invitation from a TV studio to have a show based on the duo's adventures but it turns out to be a trap. Giant-Man defeats Egghead who has pit an oversized animated store mannequin against them.
Henry Pym is knocked unconscious by an explosion during a botanical experiment that goes totally out of control. Then he is forced to capture an untalented thief who stole his Giant-Man suit and trapped the Wasp.
Learning that Hawkeye has invaded Stark's factory, Giant-Man and Wasp contact Iron Man to offer some help from the Avengers, but he declines it.
The Avengers vote a leave of absence for Iron Man who has been missing after the announcement of Tony Stark's death. Spider-Man offers to join the team, announcing that their armored comrade has been taken to Mexico by the Masters of Evil, but at the Temple of Tirod, the Avengers are ambushed by the webcrawler. As they free themselves, they understand that they were actually saved by the real Spider-Man who has disabled the robot replica of himself sent by Kang.
When the Avengers mockingly disregard a warning sent by his ants, Giant-Man discovers that the Mole Man is alive and plans to destroy the surface world by accelerating the rotation of the Earth. The rest of the team finally dig their way to the villain's lair where they find that he has associated himself with the Red Ghost. The team destroys the Mole Man's equipment and seals off the villains' access tunnels to the surface world.
The Avengers are attending a fake charity event at Count Nefaria's castle where they are put in stasis. As they leave, the confused Avengers are attacked by the US Armed Forces and have to retreat to their HQ where they learn that they supposedly threatened to take over the government. Suspecting that Nefaria is behind this, they go back to his castle where they free the Teen Brigade, defeat the Count and force a confession that clears their names, but the Wasp has been hit by a stray bullet in the fight.
At the hospital, the Avengers learn that the Wasp is in critical condition and only one specialist may save her. But Dr. Svenson had agreed to help an alien race hiding in the North Pole and the Avengers find themselves caught in the middle of an interplanetary war. When the Yirbek locate their foe on Earth, the Avengers force the Kallusians to send them back to the hospital with the doctor and to take their conflict elsewhere. Svenson's operation on Janet is successful.
Henry Pym develops a device that allows him to change the size of anything around him. Janet gives him a new Giant-Man costume that she designed for him.
Giant-Man and the Wasp defeat Madame Macabre who can change the size of non-living objects.
When Rick Jones is pulled into an aircraft by an attractor beam, the Avengers follow after it and are attacked by the Masters of Evil. To avoid injuring citizens, Thor uses his hammer to teleport his teammates and the mortal villains in a neutral place where they easily capture them. A bit later, the Wasp suggests they all take a leave of absence to take some vacation and both Giant-Man and Iron Man agree. Before they leave, they decide to accept Hawkeye, Quicksilver and the Scarlet Witch as their replacement in the team.
Pym's ability to shrink down to ant size is stolen by an alien.
Still unable to get back his ant-size shrinking power, Pym also realizes that changing size to Giant-Man puts a lot of strain on his body and that he should only change to a 35-feet size when necessary. With those new limitations, Giant-Man has to face an upgraded Human Top who, thanks to his new ability to fly, has now captured the Wasp. When Hank finds the Human Top, the villain tries to freeze Giant-Man into a giant cake of ice and encase him in epoxy. But the hero has managed to regain his ability to shrink to ant size, which prevented him and the Wasp to get frozen. Then Giant-Man uses the Human Top's freezing chamber to capture him.
