20TH ANNIVERSARY ISSUE! Once upon a time the Thunderbolts were the Masters of Evil...and if Baron Zemo has his way, their legacy will be reclaimed...with the infinite power of a Cosmic Cube! Captain America's sinister plan for Bucky and Kobik begins to unfold. "Return of the Masters," the Thunderbolts 20th anniversary event, begins here! Along with our pulse-pounding lead story, this special oversized issue includes a brand-new Thunderbolts tale by series co-creators Kurt Busiek and Mark Bagley!