Tai and Matt argue whether they should climb Infinity Mountain. Joe and Gomamon decide to climb the mountain by themselves. While on the mountain, they are attacked by a Unimon.

Gennai urges the group to travel to Server in order to defeat another enemy, informing them about Crests, which will allow their Digimon to Digivolve even further. While traveling on the ocean, the DigiDestined are swallowed up by Whamon, who is under the control of a Black Gear. Tai frees him with his Digivice, and as gratitude, Whamon takes the DigiDestined into an undersea store where the Crest tags are located. They fall under attack to Drimogimon and free him from a Black Gear. After recovering the tags, Whamon proceeds to take them to Server.

Tai and Koromon arrive home, where they meet Tai's younger sister, Kari, and also learn that not much time has passed since they were in the Digital World. Later, Tai gets a message from Izzy telling him not to return, and he discovers that Digimon are appearing in the Real World. He concludes that they must return to the Digital World and help their friends. After Koromon Digivolves to Agumon to battle an Ogremon, a portal opens and transports both of them back to the Digital World.