After two months of peace since the last beast attack, the heads of Hero Factory still didn't trust the peace. But when the grounds around Hero Factory itself started rumbling and a large crack formed at the HF plaza they quickly round up the defenses. But when it suddenly gets dark and a humongous shadowy silhouette rises from it, fear spreads among the troops. They manage to destroy it but the victory costs HF dearly, cripling the labs and production facilities. This battle was known since as the "The Rise of the Great Shadow Beast".