While being a huge fan of Alpha Flight's glory days with John Byrne, and being incredibly underwhelmed by the recent Omega Flight miniseries that tried to reboot the group, I largely ignored this story when it was coming out as a 12-part story in Marvel Comics Presents. Any story that takes a year to tell in small bits is just too much for me to follow on a monthly basis. So when I saw the story would be released in trade paperback format, I jumped on it.
The story is complex, yet interesting: Guardian is actually a mutant known as "The Collective", who made his debut in the New Avengers title and actually was responsible for the death of the original Alpha Flight. In the Omega Flight miniseries, we saw him take on the suit of Guardian to make amends for what he had done to Alpha Flight. This story picks up not long after Omega Flight ends, with Michael experiencing some weird side effects and possibly losing his powers altogether.
US Agent is chosen to continue his training, but Guardian seems to be scared to use his power. A few shady representatives from the Canadian government are keeping Guardian's true purpose under wraps (though here's a hint: the "Weapon Omega" title from the book is what they actually call him). Through a rather creative recycling program with the supervillains and heroes refusing to register under the Superhero Registration Act (this occurs right after Civil War), they are able to power up their hero and turn him into the ultimate weapon.
Consumed in one setting like this, the 12-part story is really well-written. There is an exciting little bit of mystery here as the source of Michael's power failure slowly becomes more apparent, and the plot twist at the end is wonderful. Guardian exhibits powers he never had before, but it all makes sense and doesn't stretch credibility too far or anything.
All in all, I highly recommend this one if you're a fan of the character. I can't say this would be your best introduction to him though, as you'll be a little lost. The writers assume you know about the character's history and pretty much dive right into the story. Pick up "New Avengers: The Collective" first, and then the Omega Flight mini to get a good idea of what's happened up to this point.