Ice Ice Baby

Summary
Koji and Takuya unity spirit evolve to MagnaGarurumon and EmperorGreymon respectively and fight Cherubimon. They realize that their teammates are vulnerable without their spirits, so Takuya takes them someplace safe while Koji holds him off. When Takuya rejoins Koji, they continue to fight and Bokomon observes that Cherubimon's attacks have become unfocused; he takes that as a good sign. Meanwhile, Kouichi is concerned for his brother, something that does not go unnoticed by Zoe. Takuya and Koji send Cherubimon crashing into the castle and it begins to crumble. The other DigiDestineds are picked up by EmperorGreymon, but before Kouichi can take safety, the floor crumbles and he begins to fall. At the last second, MagnaGarurumon catches him and carries him to safety.

Now safe, the children debate whether or not Cherubimon was defeated; Kouichi says that he knows Cherubimon and that he is definitely alive. Zoe notices again that Kouichi seems agitated and talks to him. Apparently encouraged, Kouichi attempts to talk to Koji, but before he can, IceDevimon emerges from the depths of the castle and attacks. Bokomon reveals that IceDevimon slaughtered many digimon and took their data, making him so powerful that not even Cherubimon could defeat him. Instead, he was imprisoned in the castle until its destruction. IceDevimon begins to wonder if human data tastes good and when Takuya and Koji prepare to attack him, he 'thanks' them for their help by freezing their D-Tectors. He says this is because they are the most powerful and he intends to save them for later, after he defeats the 'distractions'.

J.P., Tommy, Zoe and Kouichi each spirit evolve into their human spirits and attack IceDevimon, but he then simply freezes Beetlemon and Kazemon so he can pick them off one by one. Tommy and Kouichi both slide evolve to Korikakumon and JagerLowemon respectively, but IceDevimon becomes bored. He snatches up Takuya and Koji, suggesting that they play a 'game' to see how long they can survive being frozen and traps them in an ice force-field. As the ice begins to take hold, Koji pushes Takuya away to protect him and is attacked by tendrils of ice. Hearing Koji in pain, Kouichi becomes angry and glows with power. He rams himself into the force-field and breaks it. Takuya immediately wants to fight, but Koji tells him that they'll only get in the way, so the two back off, leaving the fight in Kouichi's hands.

Kouichi and IceDevimon begin to fight in mid-air before JagerLowemon is knocked to the ground again. Kouichi then instructs Korikakumon to free the others. Beetlemon and Kazemon slide evolve to MetalKabuterimon and Zephyrmon. Korikakumon, MetalKabuterimon, and Zephyrmon all attack IceDevimon at once and JagerLowemon delivers the finishing blow. He then slide evolves back to Lowemon and scans IceDevimon. Exhausted, Kouichi returns to his human form and collapses; Koji helps him up. Takuya exclaims that Kouichi is definitely part of the team now, with Tommy agreeing. Koji and Takuya's D-Tectors return to normal, losing the ice that they were encased in.

The gang then notices Fractal Code glowing some distance away and it's revealed that Cherubimon has yet to be defeated....

Real-world references
The title of this episode is a reference to the Vanilla Ice song of the same name.