From the publisher:
Leap into the adventures of the dynamic Defenders, comics' greatest non-team! Bonded in a mutual mission are the mightiest misfits in the Marvel U.: the Incredible Hulk, the Sub-Mariner and the Silver Surfer. But these warriors three don't rest on bylaws and butlers; they - along with the Master of the Mystic Arts, Dr. Strange, and the defiant Valkyrie - come together only in moments of utmost crisis. Facing enemies from across the incomprehensible divide, the Defenders square off against Dormammu; the Nameless One; the Enchantress; and a dark menace from Dr. Strange's past, the sorcerer Cyrus Black. It's not just baddies they do battle with, though. In a prelude to the epic Avengers/Defenders War, Hulk, Namor and the Silver Surfer go head-to-head with the mighty Avengers in a fight that pits hero against hero like none other!
Collecting SUB-MARINER #34-35, MARVEL FEATURE #1-3 and THE DEFENDERS #1-6.