Ultimate Comics Hawkeye by Jonathan Hickman

Hawkeye's back in a bad way. Armed and dangerous, Clint Barton is tasked with his most perilous mission yet. And what he discovers will revererate across the entire Ultimate Universe. Tasked on a covert and dangerous mission, Hawkeye finds himself in the middle of an international arms race--but on the brink of obtaining a serum that will change the course of mutant history, has the eagle-eyed hero aimed too high to succeed?

COLLECTING: Ultimate Hawkeye 1-4