From the DCU Blog The Source about Adventure Comics #8:
ADVENTURE COMICS #8 is the start of a four-issue arc connecting ADVENTURE to the next big Superman story - “Brainiac & The Legion of Super-Heroes.” James Robinson & Julian Lopez will provide a 10-page story about the Legion members who are in the 21st Century; Sterling Gates & Clayton Henry will provide a 10-pager about the Legion in the 31st Century; and Eric Trautmann & DC newcomer Pier Gallo (wait till you see this guy’s stuff!) will provide a 10-pager about General Lane’s Human Defense Corps.
The Superman writers have crafted a really fun and epic story in “Brainiac & The Legion of Super-Heroes” (which will run in ADVENTURE, SUPERMAN, SUPERGIRL and a tittle-to-be-named-later in March). Featuring Superman, Supergirl, Superboy, Mon-El and the Legion of Super-Heroes, it not only brings to a head all the Legion subplots that DC has been laying down since the JLA/JSA “Lightning Saga” story, but also sets the stage for this summer’s blockbuster Superman event!
I found some sample pages pencilled by Pier Gallo on Andy Diggle's flickr page (Hawkeye and Batman), it looks good but I'm not sure if he's going to be doing any Legion stuff or just this one HDC story.
Here's the cover to ADV #8 (they've also got prelim cover sketches and a pencils-only version of this). I'm looking forward to the tittle to be named later - fanboy speculation, maybe a new Legion book, leaving Adventure to Superboy?