The episode begins with Masaru having a dream about the day his father left for the digital world. He is standing outside with his mom and Chika, and we see him wave goodbye. Masaru wakes up and sees that he is back in the human world with his friends. Sleipmon is standing nearby and Raramon questions who he is. He says he is Sleipmon and is one of the royal knights. Captain Satsuma appears (who was thought to be dead) and says Sleipmon is one of the good guys. Sleipmon devolves to Kudamon and is greatly injured from rescuing everyone from the other knights. The group returns to their secret hideout and Satsuma begins to explain Kudamon’s history. Kudamon was sent as an emissary from the digital world to determine whether or not human begins were a beneficial existence to the Digimon. Megumi at first believes he was sent as a spy of Yggdrasil. Kudamon picks himself up and tells everyone although he is a royal knight his heart has grown fond of the humans and he cannot accept Yggdrasil’s command to wipe out earth. Masaru has a brief flashback of Yggdrasil telling him his plans to destroy the human world to save his own. Masaru questions why his dad is Yggdrasil and their enemy. Satsuma tells him that his father has changed and proceeds to explain that after his battle with Kouki, Nanami, and Ivan in the space-time interval, he and Kudamon met Suguru in the digital world. We see a flashback of Satsuma and Kudamon before Yggdrasil learning that he plans on destroying the human world. Satsuma asks him about Sayuri and Chika. He then asks about Masaru who is trying to save both worlds. Yggdrasil tells Satsuma he has no concern for his family and sends him away. Satsuma tells Masaru his father has changed. Just then Sayuri and Chika walk in shocked. Chika doesn’t believe it. Later on, everyone eats dinner and rests up while Masaru and his family step out for a bit because of the news about Suguru. Agumon defends some fried eggs from Raramon while Masaru is dealing with his family. Satsuma tells everyone for now on they need to consider what actions they take carefully because the two worlds will collide once BanchouLeomon runs out of energy. Miki then detects a Digimon in the harbor.

Masaru, Sayuri, and Chika are along a river bank and Chika is telling her family that she is disappointed to learn about how Suguru has changed. Masaru believes there must be a reason their dad betrayed them. Sayuri tells Masaru that no matter how Suguru appeared to him in the digital world she still believes in him. Masaru is still upset and doesn’t know what to do now that his father is his new enemy.

In the city, Gallantmon has appeared and is carrying out Yggdrasil’s order. Everyone but Masaru shows up and Kudamon tells his fellow royal knight to leave the human world alone. Gallantmon says the royal knights must obey Yggdrasil. Kudamon says he understands saving the digital world but that you can’t kill all the humans. Gallantmon says the humans attacked the Digimon first and that they should step aside or else. Touma, Yoshino, and Ikuto evolve their Digimon to their mega forms. Megumi and Miki evolve their PawnChessmon to their ultimate forms. Gallantmon begins fighting the group. Meanwhile, Agumon runs to Masaru to deliver the news about Gallantmon appearing.

Masaru thinks about the day his father left them. He brings up that day to Sayuri and the begin remembering it. Young Masaru and Suguru played a game of catch and Masaru tells his father to throw the ball with everything he has. Suguru is shocked at first but sees Masaru’s determination to catch it and does so. Masaru gets knocked to his butt but catches the ball. Suguru gives Masaru a pendant and says it is proof of a grown man. Sayuri tells Masaru and Chika that Suguru must’ve believed back then that Masaru would protect his family even if he didn’t return to the digital world. The family matters are interrupted by an explosion and RookChessmon falling nearby. Agumon appears and tells Masaru and Gallantmon is attacking the city. Masaru and Agumon run off the join the fight.

Gallantmon is easily beating MirageGaogamon, Rosemon, Ravemon, RookChessmon, and BishopChessmon. He is about to end their lives but Masaru and Agumon appear to stop him. Masaru evolves Agumon into ShineGreymon and then gives ShineGreymon the GeoGrey Sword. ShineGreymon and Gallantmon begin fighting. Gallantmon is happy to see that Masaru and ShineGreymon are somewhat of a challenge. Gallantmon manages to knock away the GeoGrey Sword but ShineGreymon tries a desperate move in return that ends up hurting himself instead of Gallantmon. Gallantmon tells them it is pointless to fight him. Masaru tells him to shut up because he won’t let him destroy the digital world. He then says he is going to confirm his dad’s feelings because he doesn’t believe his dad would want to destroy a world. Gallantmon powers up a Final Elysian to end ShineGreymon once and for all. Kudamon tells Satsuma to evolve him even though he is injured. Kudamon evolves into Sleipmon and stops the attack. Gallantmon questions why another royal knight is siding with humans. Sleipmon says humans may be selfish and arrogant but they can mend their ways and he believes in their potential. Sleipmon rushes Gallantmon and the two hold each other in a lock. Gallantmon tells him to stand down because it would do him no honor in defeating him. Sleipmon uses an attack called Odin’s Breath that begins to freeze both Digimon. Gallantmon attempts to pierce through Sleipmon’s shield with his gram but is unsuccessful. Sleipmon tells Satsuma and Masaru that he entrusts the future of both worlds to the humans and then both Digimon disappear underwater.