Ultron Pym.
If you've been reading The Mighty Avengers from the begining than I really see no reason to miss this book. Ultron makes his final attempt for this story arc to destroy his "father" and set himself up as the heir to Pym's legacy so to speak. But this series has proven one thing, that Hank Pym always tries to stay one step ahead of his enemy, and you see that here. Ultron's army of "brides" Pym manages to subvert back into just useless piles of metal basically. And yes this story ends with a sort of sacrifice in a way to defeat Ultron. And there are a few things involving a certain "wasp" that I'm gonna to leave out there in hopes you pick this book up. Is it great? No. Is it good? Yes. Give it a read.