I wont spoil much, but as the cover implies, it is mostly about Naruto's parents. Present timeline is hardly covered in this volume, except for the first few chapters.
There is one fight here that is quite interesting and cool though, between... well, just buy it and you will see. The art is still very good, just as any Naruto manga.
As to why only 4 stars, this volume is a tad slower in pacing; and as I said, its mostly flashbacks, which hardly pushes the story forward. It just gaps some holes, though longer than it should.