The Fusion Fighters pour their energy into the fight against Dark General Gravimon, who in addition to his fearsome army and ability to re-constitute his body, has set his sights on taking the power of X7 for himself.

Falling into Bright Land's underworld, the Fusion Fighters find themselves landed on ambiguous place. Soon, they spot and enter a white castle. While they found a throne and a crystal placed in the middle of the castle, Ewan send out a two ways virtual communication through the crystal from the dark castle, informing that they have landed into Hell's Field, declaring a battle. But the battle is unique as the losing group's general would be killed upon defeat. Christopher makes the decision to accept the offer to Mikey and Nene's shock. But Christopher reveals intent to make Ewan understand that the battle is not a game. As the battles take off, AxeKnightmon and Whispered's followers battle Shoutmon ×5, Beelzemon and Mervamon while Christopher has Cyberdramon attack Whispered and Sethmon. As Ewan predicts that the battle goes according to his will, he unexpectedly encounters with Mikey who strikes the black castle directly with MetalGreymon holding off Tuwarmon. While the fights goes on, a terrified Ewan flees from Mikey before taking a sword with the intent to settle things out in a duel.