It's just not a big X-event without Art Adams, who provides the variant cover to New Mutants #15. That issue kicks off the "Fall of the New Mutants" storyline by Zeb Wells and Leonard Kirk. Here's how Marvel describes the issue:
The game-changing Fall of the New Mutants begins as Zeb Wells and Leonard Kirk set the fractured New Mutants on a crash course with destiny! A secret military group with a deadly connection to one of the X-Men’s past has Illyana Rasputin in their sights and has no qualms about killing whoever gets in their way. They’re no strangers to severe misfortune, but could this be the end of the New Mutants?
Check out the complete cover after the jump.