It's the not-too-distant future, a time when internet technology has swept the world into the Network Age! Everyone carries around a portable communications deviced called a ""PET."" Each PET contains a unique personality program, or NetNavi, that freely navigates the CyberWorld. Lan, an enthusiastic 11-year-old, is introduced to his own, custom-build NetNavi, MegaMan. At first, Lan only wants to use MegaMan to play in cyber NetBattles against his friends' NetNavis. But when computer systems all over town begin to burst into flames, Lan and MegaMan team together to fight against a mysterious criminal syndicate that calls itself World Three!

The NetSavers are in investigation with the Sci-Lab over the strange comet that has appeared in Earth's atmosphere. Soon, strange activity begins occurring when giant-sized Mettaur viruses begin terrorizing DenTech City. Lan and Chaud manage to defeat them, but MegaMan finds himself captured by none-other-than Bass. He tells MegaMan that he is after his "Ultimate Program" so he can fight off Duo. As Lan and Chaud rush to his rescue, they encounter an old rival, Dr. Wily, who seems to know what's going on.

BubbleMan, who was frozen in cyber space by Colonel, finds himself freed when a strange energy appears before him. Left behind is an infant NetNavi. He carries it to NetCity before collapsing and being found by Roll and the others. Meanwhile, strange disturbances appear in the real world as two gigantic cloaked beasts begin battling. Lan, Chaud, and Raika intervene, and the beasts move their battle to the internet. When MegaMan battles with them, the infant's power combines with his own, and MegaMan defeats the beasts using two new styles modeled after the beasts.

Disguised as Higsby, Yahoot gives Maylu an evil BattleChip, which she uses in her team match with Lan--against Mr. Match and Maddy. This ""twisted chip"" has now taken over her PET and put Roll under the control of Count Zap and World Three! Every time Lan sends MegaMan into action, Roll, now calling herself Empress, steps in his path and attacks our blue hero! Finally the real Higsby appears and tells Maylu the secret to stopping Roll from her rage. With Roll back to normal, Lan and Maylu easily win the match. Up next, Chaud and ProtoMan are teamed up with a teen NetBattler and his singing NetNavi, ShiningMan--against WhaleMan and RocketMan. Not exactly team players, Chaud and ProtoMan take out their opponents and ShiningMan in one blow!

Asteroid MoltanicMan was given to a criminal, but after an incident, a war-torn MoltanicMan drifts through the internet and finds himself in the PET of young fireworks-maker Fyrefox. Fyrefox is delighted to have a NetNavi after the loss of his own, and Fyrefox's friendship gradually sways MoltanicMan away from evil. However, MoltanicMan's original NetOp reappears, unwilling to give up his partner in crime to Fyrefox.

While searching for ingredients for Pat's curry, Dingo and Trill encounter DiveMan and follow him to a nearby lake castle. Inside, they discover that two humans, Captain Blackbeard and Yuika, are cooperating with Zoano DarkMan and have taken Iris prisoner. Dingo and Trill infiltrate the castle in hopes of rescuing Iris, but they must battle with Yuika's NetNavi, CircusMan. In the end, Iris is rescued.

No one knows what to make of the mysterious new NetNavi Bass, but everyone is intruiged when it seems that he alone can resist the CyberBeast that's slowly destroying the entire Cyber Network! What will he do with that kind of power? What does he want? And whose side is he on: MegaMan's? Grave's? Taking no chances, Kid Grave sends FreezeMan to delete Bass. Then Bass makes off with an unconscious MegaMan, launching Lan and his friends on a desparate search to find him. And worst of all: Mr. Wily has returned.

Thirty years ago, Duo's comet had crashed on Earth, and Dr. Regal plans to travel through space and time to absorb its power. MegaMan, ProtoMan, SearchMan, and Colonel rush through time to thwart Dark MegaMan who was sent to help Dr. Regal gain access to the comet. However, Dark MegaMan plans to absorb the power himself and become the ultimate NetNavi, but Slur refuses to allow him to do so by deleting him. Before fading away, Dark MegaMan self-destructs and prevents Dr. Regal from succeeding. The heroes return home, and the renmants of Dark MegaMan's being rejoin with MegaMan's soul, and MegaMan forgives him.

The BlasterMan/StoneMan clones attack PharaohMan, but he escapes unscathed. Roll and the others are not so lucky and are turned to stone by PharaohMan. As this part of the Cyber Net begins to collapse, ProtoMan succeeds in saving MegaMan's frame. SharkMan, SkullMan, and WoodMan work at shutting down SciLab's main computer, while ProtoMan takes on PharaohMan single-handedly. Just when it seems ProtoMan will be deleted, MegaMan returns and the two NetNavis attack PharaohMan with the Double Program Advance. BlasterMan and StoneMan reappear and take the weakened PharaohMan to Mr. Wily at World Three Headquarters. MegaMan follows them but is immediately set upon by BlasterMan and StoneMan, so Lan engages MegaMan's new ability, StyleChange, which allows MegaMan to easily defeat the Solo NetNavis. In the end, Mr. Wily and PharaohMan's showdown of wills ends in the destruction of World Three Headquarters.

All contact with NetNavis in DenTech City's moon station has been lost! While Commander Beef rockets to the moon to investigate, Lan and his friends are trying to learn more about the mysterious new ""ExtraCodes"" rumored to make NetNavis mightier than ever! Then Commander Beef encounters a dangerous new NetNavi, PlanetMan, who's trying to take over the moon. But before the Commander can react he's locked outside the lunar station with only two hours of air left! With Mr. Famous's help, Lan and his friends rush to the space center and beam MegaMan and GutsMan to the moon's cyber station to battle PlanetMan. But even with MegaMan now wielding an ExtraCode to get the amazing AquaCustom Style, will he be able to handle its awesome, energy-draining power?

AyanoTech is hosting a NetMobile Grand Prix in NetCity! MegaMan and his friends, plus World Three and the Net Agents, all compete to see who has the fastest NetVehicle! But the winning car will have to be more than just speedy, because in this race, anything goes, including using BattleChips to sideline your opponents. It's all legal! And, as if driving under those conditions weren't tricky enough, the CutMan Brothers, who vowed to take revenge against MegaMan, join the race and create utter mayhem! In all the confusion, who will take the lead and win?!

It's Tesla's birthday, and she desires more than anything her own SynchroChip. Through a series of crimes, the Neo WWW is able to retrieve her one, and she uses it to overcome Lan in battle. In the end, he is rescued by Ms. Yuri, but not before she has a special reunion with her twin sister Ms. Mari.

The CrossFusion Members meet with Chaud to explore ancient ruins discovered in Netopia which bare Duo's symbol. Inside, a holographic image tells of an alien race that travels to planets via Duo's comet and destroys civilizations that are deemed dangerous. Slur becomes enraged that the heroes have discovered the past of her race and commands the destruction of the ruins. The children barely manage to escape in time.

Charlie is startled to discover Tesla has been sleeping in his apartment. Meanwhile, Dark MegaMan lures Ms. Yuri into a trap to steal her Crest of Duo. When she refuses to comply, Dr. Regal then appears and steals it himself. Lan, Charlie, and Tesla battle with the remaining Darkloids, deleting CosmoMan and forcing Dark MegaMan to retreat. Dr. Wily explains that Dr. Regal needs the data within the Crests of Duo to achieve access to the power within Duo's comet. Dr. Regal has planned such a thing for decades as he had already taken Baryl's Crest twenty years ago when Baryl was alive.

The CrossFusion Members continue to deal with the Zoanoroid threat in DenTech City. Meanwhile, many Beyondard residents attempt to fight back against Wily but all fall short. In the end, in order to defeat Wily, Trill and MegaMan combine their powers and Lan performs Cross Fusion, merging into a new "Juuka Style." With this ultimate power, Lan is able to destroy Wily and close the portals between both worlds. With peace restored, Lan and his friends return home, but not before saying goodbye to new friends Trill and Iris.

The N1 Grand Prix rages on, and TorchMan and MegaMan are locked in a heated battle (continued from previous episode)... It seems like MegaMan has the upper hand when Mr. Match downloads a nasty virus to take control of the solar panels on the roof of the Floating Arena's dome. He mercilessly channels the sun's rays into a beam that showers agonizing heat down upon Lan. As MegaMan and Lan suffer the scorching onslaught, Dex, Yai, and Tory jack in their NetNavis to vanquish the viruses one by one. Just as MegaMan's about to become toast, the gang clears the last of the viruses. The Dome opens up, and Lan and MegaMan turn in a blazing victory. Higsby and NumberMan fight the last battle of the day against sweet Sal and WoodMan. Thinking that they can easily defeat the flower girl, Higsby and NumberMan receive an ego smashing as Sal and WoodMan take them out in one blow!

In order to revive MegaMan, his back-up frame must be retrieved from the SciLab network. However, PharaohMan has taken over the network and turned it into a barren desert wasteland. Roll and the other NetNavis jack-in to retrieve the frame, but PharaohMan intervenes.

Lan visits Netopia's Heaven City, but as soon as he arrives, his PET is stolen. After chasing the thieves down, he befriends a man named Raoul with NetNavi ThunderMan. Meanwhile, the mayor of Heaven City has plans to bulldoze Raoul's downtown home, but Lan agrees to help fight back. Meanwhile, Mr. Match arrives to Jawaii islands to have a rematch with Lan, but he arrives too late: Lan left Jawaii islands.

The five younger brothers of CutMan declare revenge against MegaMan for deleting their older brother. Luring MegaMan into a fake China Town district, they begin attacking with a barrage of origami warriors. ProtoMan appears and assists in the rescue of MegaMan.

Tora, world-class NetChess Battling Champion and his NetNavi KingMan, have come to DenTech City to challenge Lan and MegaMan. Tora never plays for free though, and demands that whoever loses the NetBattle must give their NetNavi to the winner! Lan accepts the challenge, but soon realizes he has no idea how to play chess! Luckily, Maylu does and partners up with Lan. As the incredible battle nears its end, ShadowMan mysteriously appears on a mission to delete both KingMan and MegaMan!

Kyuta, a new student in Lan's class, is the son of famous baseball player Kyuma Hoshida, but he's depressed about having to move from his old town. To cheer him up, Lan and all of his friends in DenTech City invite him to a game of NetBaseball.

The Grave VirusBeast continues absorbing the internet. Lan and his friends team up with former WWW members to try and stop Grave. However, Mr. Gauss and MagnetMan intervene, and a strange bug left behind by Bass in MegaMan's system begins to consume him. Meanwhile, Bass attempts to absorb the VirusBeast, but is himself absorbed instead.

Lan meets a girl named Jasmine from the country of Choina. To complete her training as a pharmacist, Jasmine seeks a rare flower, and Lan agrees to help her. However, a man named Bengel in a medicine company hopes to steal the medicine that Jasmine is concocting, so he kidnaps Jasmine and threatens to delete her NetNavi Meddy if she doesn't give up her secrets. Lan and MegaMan manage to rescue the two from the perilous situation.

Yai holds a NetNavi design contest, and Viddy is so thrilled to participate that he quits his job with Neo WWW. However, upon winning the contest, Viddy is disqualified because the contest is restricted to children. Enraged, Viddy begins transforming AyanoTech's game characters into rabbits, but Lan and MegaMan intervene to stop Viddy's rampage. Viddy returns to his life at Neo WWW.

Lan becomes tired from constantly battling the Neo WWW, so Dex decides he wants to perform CrossFusion and help in the battle. He confronts Famous who uses Rush to create the Rush SynchroChip to help make it possible. Dex and Maylu accompany Lan to a dinosaur theme park where Viddy strikes, but Lan is too tired to battle. Dex attempts CrossFusion and fails, so in order to save the day, Maylu tries it. Surprisingly, she CrossFuses flawlessly and helps Lan defeat Viddy.