After a short time skip, Kouji and Shiro now live at the Kurogane House and work alongside the Photon Power Lab in the fight against the mechanical beasts. However, friction has been born between Kouji and the Robot Corps, who he finds useless and has no desire to fight beside. Meanwhile Baron Ashura, eager to prove him/herself to Dr. Hell, begins a co-ordinated mechanical beast attack on Tokyo, Osaka and Nagoya. At the same time, three mysterious blonde women arrive at the Kurogane House.
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.