Animated-style adventures from one of the X-Men's greatest eras! Wolverine takes on the savage Hulk - but whose side are Havok and X-Factor on? And what does the gamma-powered Leader have to do with it all? Meanwhile, Beast and Gambit face the evil machinations of Mister Sinister...with a little help from Spider-Man! Things take an occult turn for Cyclops, courtesy of the demonic N'Garai and the Dweller-in-Darkness! And when Magneto and his Brotherhood commit an act of war, the X-Men must respond - but as the situation explodes out of control, it just might bring about the Apocalypse...that's with a capital A! Who will be left standing in the ultimate survival of the fittest battle?