The Twilight Brigade continues its search for the Virus Cores, mysterious items not included in the official game specs. They believe they need to collect them before they can find the coveted Key of the Twilight. Meanwhile, their rival Guild, TaN, pressures them even harder using their secret service led by a dangerous Player Killer Ender.Haseo has an idea on how to use the Virus Cores in one of the Lost Grounds. As their leader Ovan decides to take action, even Gord and Bset, who left the guild in disappointment, join them again to fight against the enemy warriors.