Story overlaps with the second OAV. Looking at the release dates for them, I'm guessing they were conceived at the same time. Although this drama CD was released before the OAV, the intent may have been to make it a supplement. The fact that the CD story avoids focusing directly on the OAV story, and instead narrates around it, is indicative of this.
As with the first CD, audio quality is excellent.
There is a very short version of Satou Hiromi's "mizuiro" embedded in track 6, but I'm not counting it as a vocal track. It still reduces the audio quality rating by one star, though.
This CD only cost me Y480.