Whilst it is true that Season 4 dips in quality, it is still a highly enjoyable show. I found this season to be not as exciting as previous ones, the whole Armenian money train arc from s2/3 was dynamic and gripping, but this season feels a little limp in comparison. This is not an indictment, however, as The Shield still delivers 'edgy' and gritty storylines. The addition of Glenn Close is, I feel, not as good as it should have been. The character didn't seem to be as fully rounded as I had expected, and perhaps Glenn Close didn't have the best of material (compared to Damages which suits her perfectly). The other actors do a good job though, especially the undervalued Walton Goggins, in my opinion one of the highlights of The Shield as a whole. Shane is an awesomely conflicted character, and really meshes well with Michael Chiklis' (as ever) excellent Vic. The main 'villain' of the season is Antwon Mitchell, an interesting character that seems to get away with anything, as a result from the storyline dragging a fair bit. As comeuppances go, his is an odd one, but the storylines are tight so this, in effect, makes sense. The two big plot points this season, without giving too much away, are the murder of a girl and the murders of two police officers. Both are very good, and are supplemented by the usual B-storylines, 'weekly mysteries' if you will. My favourite episode was 'A Thousand Deaths', definite highlight, one of the best episodes ever. If you are a fan of The Shield, it is mid point to an excellent series and an obvious purchase. If new, I would suggest starting at the beginning, as this season would not make for the best of introductions.