iTunes has 2 listings for this group, one with a diacritical mark and one without. One has three of the group's CDs. The other shows two. 3 + 2 = 5.
I poked around in Windows Explorer, which has the same two listing in the iTunes music folder. That is, two subfolders for the group, one with the diacritical, one without. Both list the same 4 out of 5 albums. Neither lists The Starlit Jewel.
I highlighted a song on the CD in iTunes and asked iTunes to kindly show me where it lives. iTunes thinks it lives in the group folder with the diacritical, in the iTunes music folder, and it showed me this in Windows Explorer. But, when I open up Windows Explorer on my own, it does not show the album. I have no idea why.