Baron Ashura's mechanical beasts continue to wreak havoc in Tokyo, Osaka and Nagoya, forcing the Robot Corps sortie to defeat them. However, their machines prove to be ineffective at fighting the mechanical beasts. Kouji remains at the Kurogane House, knowing that if he left to help them then the Photon Power Labs would be left open to attack. While he waits, three assassin androids - the Gamia Sisters - arrive at the Kurogane House to kill Kouji. But before they can complete their mission, they are stopped by the Kurogane Five who are revealed to have special abilities and weapons. Cross is a cyborg made from Super Alloy Z, Sensei has a Super Alloy Z katana, Yasu's body contains a Photon Power Bomb, Kikunosuke can move at super speeds and had Super Alloy Z razor wire, and Django has special Super Alloy Z bullets. While they are fighting the Gamia sisters, Kouji steals the Pilder and prepares to dock with Mazinger Z - determined to defeat the attacking mechanical beasts.

Kouji arrives at the Photon Power Lab with the Pilder and attempts to combine with Mazinger Z. However, Baron Ashura attacks with Belgas V5 and steals Mazinger Z, forcing Kouji to chase after it and free Mazinger before he can use the machine. As Kouji fights mechanical beast after mechanical beast, Tsubasa and the Kurogane Five arrive at the Photon Power Labs carrying the corpse of Gamia Q3. They speak with the scientists and seem to agree on who could have made the androids. They then go on to discuss various other upcoming technologies such as the Jet Scrander - a flight module for Mazinger, and the Mazinger Army - an upgraded version of the Robot Corps. Meanwhile, Kouji has defeated several mechanical beasts - Belgas V5, Glossam X2, Ghostfire V9 and Taurus D7. The last remaining mechanical beast is KingDan X10, but before Kouji can defeat it the beast opens up to reveal Sayaka chained to its insides.

Having surrendered Mazinger Z to Baron Ashura, Kouji is handcuffed and locked in a cell in Undersea Fortress Saluud. Boss, Nuke and Mucha on the other hand, managed to avoid detection by hiding in the Pilder. They break out, defeat several guards and then disguise themselves using their uniform to rescue Kouji and Sayaka. After freeing Kouji however, the Saluud comes under attack from Count Brocken and begins to sink. Eventually, Boss and Kouji rescue Sayaka and make it back to the Pilder and Mazinger. Before they can get there though, they are confronted by the fifth and final Gamia sister who is defeated by the joint efforts of Kouji and Sayaka. The group then get in Mazinger Z and prepare to escape, but not before Baron Ashura reveals that he had set the fortress to self-destruct. To make matters worse, when Mazinger Z escapes the fortress it becomes stuck in the soft ocean floor.

In order to confirm the nature of the Gamia sisters, Tsubasa and Cross travel to Germany to meet a scientist named Heinrich Schtroheim. Back in Atami, Shiro falls in love with a mysterious young girl named Lorelei, who stops by the Kurogane house looking for Tsubasa who had already left. As the two begin to develop a strong friendship, Kouji learns the truth of Lorelei's background, only to find that she and Shiro have traveled to Germany in order to visit Lorelei's father. As Kouji and Ankokuji fly to Europe to follow them, they fall prey to a surprise attack by Dr. Hell's forces, while Shiro meets Lorelei's father: The monstrous Heinrich Schtroheim, who then, to Shiro's disbelief, introduces him to his real mother: Tsubasa.

With Shiro and Tsubasa together in one place, Schtroheim begins to reveal details of the Kabuto family's twisted past - that he and Tsubasa were once engaged, that she eloped with Kouji and Shiro's father Kenzo Kabuto and that before the end of the expedition, she killed Kenzo with her own hands. Their conversation is cut short by the arrival of Baron Ashura, who demands to take Schtroheim's creation - the giant robot Donau α1. Ashura reveals that Schtroheim had agreed to complete the machine for Dr. Hell, as repayment for bringing him back to life after an accident that killed him. However, Schtroheim insists that the machine is not complete and chases Ashura and his forces out of his house. With Ashura gone, Schtroheim and Tsubasa have a cryptic conversation about Mycanae and the Kabuto family but are interrupted by the arrival of the once thought dead Kenzo Kabuto.

As Kenzo, appearing via a hologram, greets Stroheim and Tsubasa, the pair soon learn that the Gamia robots were of Kenzo's design. Just as he disappears, the Ashura Corps storm Stroheim's castle, demanding to meet Dr. Schtroheim. Meanwhile, Ankokuji, who has snuck in to the Ashura Corps., manages to find and rescue Shiro, before heading out to reactivate Gamia. As Shiro meets up with Lorelei, Baron Ashura manages to hijack the Donau, planning to bring it back to Dr. Hell, just as Kouji and Cross arrive at the Castle. At the same time, Ankokuji watches as the Gamia seems to surge back to life, only for it to tell him to leave, before the area around it begins to surge with energy. Schtroheim then attempts to stop Ashura, trying to knock it out of the cockpit, only to be hit with a blast of energy by Ashura, and sent plummeting to his death.

As Kouji continues to fight off Machine Beasts, Dr. Hell sends him a "surprise" in the form of the mechanical life form Kedora, an organism originally made for the Mycenaeans to control their Machine Beasts. As the Kedora takes control of Mazinger, Kouji attempts to stop the rampaging machine and destroy the Kedora itself. After getting help from Nishikiori, Kouji forces the Kedora out of Mazinger, and manages to destroy. Meanwhile, Dr. Hell, Baron Ashura and Viscount Pygman are met by the mysterious Archduke Gorgon.

Dr. Hell tried to stop Archduke Gorgon from regaining control of Bardos island. He orders his Thalos giants to subdue Archduke Gorgon. To his surprise, the Thalos giants only follow Archduke Gorgon. Archduke Gorgon was defeated by multiple Count Brocken bodies. Kouji, Tsubasa and Baron Ashura enters the Mycenae pillar to follow the escaped Kedora. Inside, they were translated in the past where Archduke Gorgon, Tristan and Isolde was planning a rebellion against Zeus. Zeus overhears them and warns them. Cross, Django, Sensei and Yasu joins to protect Tsubasa. Kouji learns the history of Zeus. Unfortunately, the group was discovered when Baron Ashura was overwhelmed seeing Tristan and Isolde again in the past. This episode features a time travel where the present meets the past.

Baron Ashura, Tsubasa, Kouji and the Kurogane four try to flee but was stopped by the mechanical beast Garadoubla. Baron Ashura was caught and held captive. Cross sacrifices his life by saving Tsubasa and Kouji from being smashed by Garadoubla. Yasu then sacrificed himself by blowing the atomic bomb planted in his stomach destroying Garadoubla. Kouji, Tsubasa and Sensei escaped using the Hover Pilder. Tristan and Isolde, serving as priests of the mechanical beasts agrees with Archduke Gorgon's plan to preserve the Mycenae empire if their plan of subversing Zeus fail. The two went into the hybenation stage inside a cocoon. Meanwhile, Archduke Gorgon tries to please Zeus by sacrificing Baron Ashura, telling Zeus that it is Tristan covering Isolde's half face. Zeus is convinced and agrees to remove his golden protective armor. Archduke Gorgon summons Hades and Hades severes Zeus arm. Kouji saves Baron Ashura from being sacrificed in fire. Hades tries to kill Zeus by his fire power.

Kouji and Tsubasa returned to Kurogane house. Tsubasa became sick after the battle with the last Kedora and appeared to be hallucinated and acting strange. This is done by Pygman's voodoo powers. She saw first the ghost of her brother Tetsuya who appears to have a grudge with Kenzo Kabuto. Back at Bardos island, Dr. Hell vows revenge to Nishikiori Tsubasa. Baron Ashura had escaped from Bardos island after realizing she was tricked and betrayed the Mycenae empire. Count Brocken with the help of Pygman devised a plan to trick Tsubasa and the rest into revealing the whereabouts of the Japanium ore, the source of Photon energy. Baron Ashura was spotted and fell of a cliff. Pygman disguises himself as Baron Ashura. Kouji immediately came into the rescue of Baron Ashura by catching them using the Hover Pilder. Baron Ashura was brought into Kurogane house to hide. Meanwhile, Tsubasa continued to have hallucinations about the past and Kenzo Kabuto.

Energer Z appeared with Kenzo Kabuto as pilot. Pygman who appears in an hologram implies that Energer Z is looking for Zeus arm, the source of photon energy. Tsubasa appears and gets rid of Pygman's hologram and eventually his idea of handing over Zeus arm to Energer Z. Kouji activates Mazinger Z and fights off Energer Z. The two exchanges blows and fire power. Mazinger Z in the end was losing the battle and Baron Ashura convinces Tsubasa to reveal the whereabouts of Zeus arm in order to help Kouji. Memory came back to the sick Tsubasa when they have discovered Zeus arm as the source of photon energy. The same photon energy Juzo and Kenzo used to built Energer Z with Tetsuya Tsurugi as pilot. Dr. Hell revealed his true plans of world domination. Tetsuya used Energer Z to hide Zeus arm from Dr. Hell. Juzo hostages Dr. Hell but was attacked by Baron Ashura that blinded his one eye. Tsubasa appeared to help Juzo but Kenzo Kabuto appeared hostaging Juzo, his father.

Zeus arm appeared to the shocked Kouji. Meanwhile, the Kurogane four, Cross, Yasu, Django and Sensei along with Kiku appeared and captured Pygman. It was revealed that Tsubasa, as a biochemist had fixed them up again. Tsubasa explained that with the help of Tetsuya's ghost that she realized that Testuya was warning her of Pygman's plan to reveal the whereabouts of Zeus arm. Zeus arm captures Energer Z. Count Broken, masquerading as Kenzo Kabuto as pilot of Energer Z, escapes hoping that Energer Z will explode as both Energer Z and Zeus arm are photon energies. Meanwhile in Kurogane's house, Pygman escapes and tries to kill Tsubasa. Shiro shielded Tsubasa and acknowledged her as mother. Django fires at Pygman's spear with Shiro delivering the final blow. Pygman escapes into the rooftop. Count Brocken released his mechanical beasts to attack the Photon Power laboratory but was stopped by the new improved Mazinger Corps, Shin Million, Shin Daion and Shin Baion.

Bardos island has started its attack. Meanwhile Archduke Gorgon came back again to confront Dr. Hell. Pygman arrives and Archduke Gorgon disappeared. It was revealed that the real Baron Ashura was captured. Memories came back again to Baron Ashura as being Tristan and Isolde serving as priests of Mycenae and how they betrayed Zeus.

Sayaka has a new robot called Venus A after Aphrodite A was destroyed along with the submarine Salude. The Mazinger Corps, Shin Million, Shin Baion, and Shin Daion was dispatched to confront the first wave of mechanical beasts. Inspector Ankokuji appears in the Photon labs and convinces Dr. Yumi to release the Photon energy. Back at the Kurogane house, Tsubasa explains the danger and the imminent return of Kenzo Kabuto. Dr. Hell appears as a hollogram to Kouji and Tsubasa and challenges Kouji into a one-on-one fight with Baron Ashura's new robot. The Mazinger Corps arrives and tried to stop Baron Ashura to no avail. Sayaka came with Venus A and used her Z cutters and cuts Baron Ashura's robot in half. Ashura's robot electrified Venus A and reminds Kouji to accept the challenge. Sayaka was rested into Kurogane's house and overhears Boss convincing Kouji to accept the challenge. She persuades Kouji not to accept the challenge. Kouji meets up with Tsubasa for a new plan.

Dr. Hell launched his full attack. Count Brocken in his flying Ghoul and Pygman using the new submarine Bood. At the Kurogane house, the whole gang has prepared for the final assault. Django and Gamia Q3 were imprisoned by Sensei and Django as ordered by Tsubasa as they can't trust Kenzo Kabuto. Kouji arrives at the place where Dr. Hell and Baron Ashura had issued the one-on-one challenge. Much to his dismay, Baron Ashura was not there and several mechanical beasts are waiting to ambush Mazinger Z. It was revealed that Dr. Hell challenged Kouji to keep him busy so he would not interfere with his attack elsewhere. Pygman tries to take advantage and tried to kill Sayaka. Lori and Loru arrives to stop Pygman and rescue Sayaka. Pygman attacks the Photon laboratory using his control of animals. Manwhile, Kouji is losing the battle with the mechanical beasts. Tsubasa activated several bombs in Atami destroying several robots of Baron Ashura.

The Mazinger Corps is defeated. God Scrander came and integrated with Mazinger Z to win against the mechanical beasts. Tsubasa was taken by Kenzo, who was reveled later to be a robot. Baron Ashura went to Kurogane house looking for Tsubasa and decided to burn Kurogane. Back to the Photon labs, Yumi survived the blast but was about to be killed when Sayaka returns with Venus A. Ankokuji and Gamia Q3 went to the rescue and shoots Pygman's body with a decomposing chemical. The chemical was the same chemical used by Dr. Hell to rot off Tristan and Isolde's half bodies. Pygman in his true form tried to escape but was killed by Blade, Tetsuya Tsurugi with a robot background, Great Mazinger. Blade disappeared and when asked why he suddenly disappeared, Ankokuji explains that that is another story, giving a hint to the next Great Mazinger series. Tsubasa arrives at the true Kenzo Kabuto. He has cut-off his infected body with Kedora. It was revealed that Dr.

The beginning shows of Dr. Hell and Kenzo Kabuto arriving at the Mycenea hibernation place. Dr. Hell's King of Hell arises to defeat the numerous Mazinger army. The Mazinger army was defeated by Dr. Hell when the Million Squad and Venus A decides to use Photonic beam attack to Dr. Hell. Unknown to them, the King of Hell has a Photon absorber that will absorb all kinds of photon attacks thereby giving it more photon energy power. The Photon fortress attacks and the King of Hell absorbed all the photon beam attacks. The Photon fortress is now being sucked into Dr. Hell. It was revealed that Kenzo realized his mistake when he saw the arm of Zeus. Kenzo has built the King of Hell for Dr. Hell to absorb photon energy. Realizing his mistake, he reprogrammed Gamia Q3 to reverse the polarity of photon where the photon energy will be drained from the King of Hell's body. Gamia Q3 went into the Photon Fortress to reverse the flow of photon energy. Suddenly, inside the King of Hell's body, Dr.