This picks up right after #3.  I'm not sure if it's me or graphic novels in general, but I'm having such a hard time keeping up with what's happening in each of our locations in these volumes.  I love the main storyline with Tad and I pretty much know what's going on with him, but I just read the synopsis of this over on Amazon and I was thinking something completely different than what they say about one of the side plots, so maybe I just can't follow these very easily.  I've preordered them all on kindle, but I'm definitely going to buy the bind up when it comes out and get them all in physical form to read again.