The Lava Men are menaced by the Living Stone, a mysterious rock that is swiftly growing in size and emitting destructive sonic waves that release tremendous explosive force when it is struck. Unable to destroy it without potentially destroying their own underground realm, the Lava Men eventually decide to raise the Living Rock above ground, planning to conquer the world after the rock devastates human civilization. Molto, the only Lava Man who has recently visited the surface world, thinks humanity is undeserving of this fate and that it is also unwise to provoke humanity’s powerful defenders, such as Thor, who once spared Molto’s life; however, the Lava Men’s chief remains committed to his conquest plan, egged on by the ruthless and ambitious witch doctor Jinku. When the Living Rock’s sonic emissions cause chaos nationwide, the Avengers intervene, battling the Lava Men. Scientist Bruce Banner transforms into the Hulk under stress and attacks the Avengers, who trick him into striking the Living Rock at the precise point that causes a harmless implosion instead of an explosion, destroying the rock and averting disaster. Hulk reverts to Banner in the aftermath and slips away. After frightening away Jinku, Thor orders the other Lava Men to depart in peace, and they comply.