I wonder sometimes if it's possible for me to recommend this series too much. I don't think it is. But sometimes I worry I'm turning into *that person* who won't shut up about something long after everyone around them is sick of hearing about it.
After the party is reunited at the end of the last book, this one starts with them heading off to the next gate. Haley has an ulterior motive to be happy about where they're going - this is the area her father was imprisoned in and she hopes to ransom him. But things get complicated when they find out that the power behind the throne in the Kingdom of Blood is none other than Tarquin, Elan and Nale's father (dun dun DUUNNNNNNN). This master of genre savviness at first seems to be a loving man who regrets being estranged from Elan - at least TO Elan - but everyone knows the man who raised Nale is probably not totally honest. Luckily, he IS awesome.
While Haley and Elan are dealing with that, Roy and Belkar get arrested for failing to have the proper papers to be in the city and are added to the ranks of the kingdom's gladiators. Durkon makes friends with fellow cleric Malak, a priest of Nergal. And V attempts to reconcile himself* with the atrocities he committed during the last book.
I love the way this book actually brings about pretty substantial character change for basically everyone, not least of which is Belkar. He's been faking character development for a while now, but in this book, it seems that seeing true self-sacrifice might actually have gotten through his sociopathic shell. V thinks he understands what he did in the last book and has started to make ammends, but his reaction to finding out how deep he actually made that rabbit hole is way more of a personal change. Haley faces her father and some of how his way of raising her did more harm than good. Elan... well, it's obvious isn't it? Even Roy gets in on the act, having to truly come to terms with the hardest part of being a leader.
Most of the strips in this book are available for free online, but this book is SO worth the buy. Not only is it a high-quality book, but there are a few extra strips in there and the commentary from Rich, the author, are really fun to read even if a lot of the time it's stuff you might already know.
So in short - Order of the Stick is awesome.
* I know V's gender is unconfirmed. However, for the ease of discussion, I'm using the pronouns I see V as. Please feel free to substitute "she" or any gender-nonspecific term you prefer.