Darke is the 6th book (and second to last) in the Septimus Heap series. In my opinion it is one of the best, if not the best offering from author Angie Sage. Considering the series as a whole, I wouldn't say it's been hit and miss exactly, since really all the books were enjoyable, it's just that some were harder to get into that others. To be honest there were only 2 books I found dragged a bit at the beginning, but maybe if I had read the whole series one book after the other I wouldn't have felt that way..
Darke was an entertaining and compelling read from start to finish. As the title suggests, in this offering by Sage; things get darker. Firstly as part of Septimus' wizard training, he must do one week of Darke magyk training. As he gets ready to enter the Darke, more and more bizarre, unexplained and decidedly dark things are happening quite outside of Septimus' dark preparations. Extra-ordinary wizard Marcia is quite hesitant to allow her apprentice to enter his darke week, when all this darkness is abound in the palace already, but she soon finds that she will have no choice in the matter.
This was an absolutely fantastic addition to the Septimus Heap collection. While I won't give the ending away, I am left wondering where Sage will go for her final, and as of yet untitled 7th book. I felt there would be a clear continuation to this story, but the ending seems to have put certain eventualities to rest. I guess we'll have to wait and see :)