The official
website for the upcoming OVA sequel
Nogizaka Haruka no Himitsu: Finale has just revealed the release dates for the OVA's four planned episodes. The first Blu-ray and DVD volume will be out in Japan on August 29, and the others will follow on a monthly basis - on September 26, October 31 and November 28, respectively.

Like the first two TV anime series that aired in
2008 and
2009, this third anime adaptation is also based on Yusaku Igarashi's school / comedy / romance light novel series also known as Haruka Nogizaka's Secret. The original story focused on a respected high school girl who is actually an obsessive anime otaku - something known only by her dear friend Yuuto.
The upcoming OVA has been conflictingly reported to cover either the story leading up to the original light novels' final arc, or the final arc itself. Believe whichever you please...