Jeri is a friend to Takato and they both have the same class. Her real mom died and she had trouble getting use to her step mom. After Takato got Guilmon she became more interested in Digimon and the Card Game. She gets help from Rika to learn how to play and during Episode 21, "Jeri's Quest", she decides that Calumon must be her partner Digimon. Though later once the Rat Deva, Kumbhiramon, appears and Calumon runs away scared, Jeri determines that he is not her partner. Instead, a Leomon appears and protects Jeri from Kumbhiramon. She then decides that Leomon is her partner, though he denies it and runs off, Jeri right after him. Later Kumbhiramon returns and starts to make trouble. Leomon takes it upon himself to stop the Rat Deva and goes into battle. Jeri worries for Leomon and tries to use Takato's D-Power to aid Leomon in battle, but it fails and she realized that Leomon is not her partner. Leomon see's Jeri crying and destroys Kumbhiramon. He then leaves again, not wanting to be moved by Jeri's tears. Much later, after the defeat of Vikaralamon(Boar Deva) and Calumon getting mon napped by Makuramon (Monkey Deva), Leomon shows up to help but get's injured. Jeri runs to his side and that's when a yellow D-Power appears before her. She uses it to heal Leomon and from that point on she had a partner. Jeri can be strange, for she carries around a little dog puppet and not only talks to others with it, but she talks to it as well. She and Takato share a bond, somewhat, and Takato likes her more than just a friend.
Later in the season, after she get's Leomon and travels to the Digital World with the others, Leomon dies by the hands of Beezlemon and enrages Takato. After that she became really depressed and also became and easy target for the D-Reaper to capture. The end of the story is pretty much about the Tamers trying to rescue Jeri from the D-Reaper and defeating it. If it wasn't for Beezlemon getting Calumon inside the D-Reaper and Calumon giving Jeri her confidence back to fight back, then she would still be trapped within the D-Reaper. Eventually Impmon apologizes for his actions on killing Leomon and she accepts. She watches along with the others as the Digimon revert to their In-Training forms and return to the Digital World. Leomon's first appearance was in Episode 21, Jeri's Quest.
XROS WARS (Young Hunters)