Digimon: Digital Monsters S01 E28 It's All in the Cards

The DigiDestined travels to Gennai's home, where he unravels secrets about the Digital World. They return to Myotismon's castle to open the gate and battle Dokugumon. The fight causes the castle to crumble as WereGarurumon destroys Dokugumon, but they manage to open the gateway and escape through it.