Takato, Jian, and Ruki meet up to discuss their Digimon fighting as of late, and to celebrate their forming a team, Takato and Guilmon bring out a flag that theyd made depicting their group as Digimon Tamers...but Terriermon finds it corny and Ruki finds it pathetic, while Guilmon trips onto the flag and Culumon is happy to see everyone having fun.
At a train station, fog indicating a Digital Field appears on the tracks, and a drunkard yells that a huge snake has appeared...
Takato calls Jian and Ruki early the next morning, asking them to go patrolling with him as Tamers. However, Jian happens to be busy and Rukis going out with her grandmother, and Takato finds Juri, Hirokazu, and Kenta accompanied by a large group of other kids from his class at his door wanting to see him.
As it turns out, they want to see Guilmon, and Takato takes them to Guilmons hideout and shows them. Guilmon is happy to meet Takatos friends, who are fascinated by him. Hirokazu swears the group to secrecy, to which they all wholeheartedly agree.
Ruki goes to see a play with her grandmother, while Jian goes off to visit his tai chi teacher. Jian takes Terriermon with him after seeing him as a victim of Shaochungs playing, while the play Rukis watching reminds her of her fights together with Renamon.
Guilmon has fun playing with Takato and his friends, but Impmon shows up and yells at him for playing with human kids. Guilmon seems to enjoy himself anyway, and Renamon approaches Impmon, asking if he envies Guilmon. Impmon denies it, and Renamon points out that hes paying quite a bit of attention to them before leaving.
Ruki and her grandmother are at the station when her Digivice alerts her to a Digimon. Shes relieved to find that its only Culumon , only for her Digivice to beep again and indicate another presence. The fog of a Digital Field enters the station and as a giant snake Digimon appears, Ruki summons Renamon and has her grandmother taken to safety. Renamon begins battle with the Digimon, and Ruki is initially unable to get any data on it on her Digivice before it finally identifies it as Sandiramon, yet another Perfect level Digimon. Ruki decides that Renamon will need to evolve to stand a chance, and quickly slashes the appropriate card to have her do so. Sandiramon runs down the train tracks, and Ruki, riding Kyuubimon, chases him.
Jian and Terriermon get off at a train station and Terriermon senses Sandiramons presence. As Sandiramon enters the station and the civilians flee in a panic, Sandiramon begins to destroy the train, which contains a crying toddler. To save him, Jian uses an Option Card to give Terriermon a shield and block Sandiramons attack. Jian reunites the toddler with his mother, and Ruki, running by, tosses Jian a phone to call Takato with.
Ruki uses a speed Option Card on Kyuubimon as they continue the chase, while Jian goes off to look for Takato. Sandiramon continues to cause more mayhem on the subway line, with Kyuubimons attacks not even laying a scratch on him. Jian and Galgomon arrive to help, and while Guilmon plays happily with Takato and his friends, he senses Sandiramon nearby. A bit of taunting from Impmon about how Takatos playing around reveals to them that Sandiramon is underground, and as Guilmon senses a battle down there, Takato realizes that Jian and Ruki are fighting there too.
The other kids are interested in seeing a real Digimon battle, but Takato tells them to stay out of it since its not a game and uses an Option Card to give Guilmon a drill to go underground. Before he departs with Guilmon to join the fight, Hirokazu gives him an Option Card, and Takato gratefully accepts it and goes in. The others cheer him on, while Impmon sulks.
Culumon, Kyuubimon, and Galgomon all feel a strange feeling from Sandiramon, and Takato and Guilmon appear from above to intervene. Takato has Guilmon evolve to Growmon and uses Hirokazus Option Card to give Guilmon extra power. The combined efforts of the three Digimon manage to knock Sandiramon over, but he only laughs at them and tells them that hes one of twelve servant Devas sent by his God, and that with his death its only just begun. As Sandiramon dissolves into data, Jian realizes that the two Devas theyve fought so far are different from all the Digimon from before.
Takato, Jian, and Ruki emerge from the tunnel with their partners, while Takatos friends are entranced by the sight of not just one but three Digimon. Theyre interrupted by a frantic call from Rukis grandmother demanding to know if Ruki is okay, and as Ruki reassures her, the large group of kids decide to find a place to hide the Digimon away as the police approach the scene of the fight.