Constitution Legacy Fleet Series: Striking Deep Into Our Territory: Fast Paced

If you're moderately well-versed in popular sci-fi of the last 10 years or so, let me toss out a couple of plot points for you to consider...Aliens nearly wiped out humanity, then disappeared back to the depths of space. Aliens have been absent for the last 75-ish years. One of the last of the warships that humanity used in the first war is on its way to being decommissioned and turned into a museum-piece. The captain was a bit of a troublemaker and is nearly the only one in the fleet preaching readiness instead of complacency. The XO is the captain's best friend, and is an alcoholic. Some people in humanity have 'sold out' and made a deal with the aliens. The aliens are going back on their deal and have come to wipe out humanity. There's a 'back door' in humans' new generation of starships that will allow the aliens to easily destroy all of them...except for the one retiring ship.