After the very eerie ending of the third book, this one is quite light-hearted for the most part. What's new is that people are now being killed as part of the plotline, and much of Voldemort's reign of terror is revealed.

The plot is well-constructed (as would be expected), but Rowling's knack of introducing a new basic form of magic in every book and then overusing it as a plot device becomes slightly annoying here. Still, this is the last book that relies on an overarching plot, and should be enjoyed as such.