Battle of the Labyrinth

The fourth book in Rick Riordan's Percy Jackson and the Olympians series is called The Battle of the Labyrinth, and it occurs summer following the previous book.

Percy has just attended orientation at the school where his mom's boyfriend teaches, and it looks like Percy might be kicked out before the school year has even started this time, thanks to a monster attack that made all mortals except one teenage girl think Percy attacked and killed a defenseless cheerleader.

At any rate, Percy runs into Annabeth and they go back to camp, where they accidentally make a huge discovery that could have meant a surprise attack on Camp Half-Blood. A quest is arranged, and this time Annabeth heads the operation, choosing for her teammates Percy, Grover, and Percy's brother Tyson.

The team heads underground, into the Labyrinth, which has caused more than one person in the past to lose their sanity. Annabeth and the rest run into one problem after another, be it in the form of a monster or a god that has decided to side against the Olympians in the inevitable war coming up.

Finally, the group separates. Grover and Tyson run off in one direction, while Percy and Annabeth go in another. Then Percy and Annabeth separate, and it looks like Percy's fatal flaw, personal loyalty, has finally claimed his life.

True to Riordan humor, Percy reappears in Camp Half-Blood in time to witness his own funeral. One the fact that he survived has been established, he tells Annabeth he has figured out how to make her quest a success.

I have to say, this book has the most bittersweet ending yet. The big plot points as far as the quest and the battle in the end are successful, but at what cost? Percy seems to be caught in a complicated love triangle - or is it a square - or some complex shape without a name. Another character dies, although this one is more justified, I guess. Probably worst of all, Annabeth loses a love to worse than death.

Anyways, Riordan does try to end on a happy-ish note, with Percy's mom potentially getting engaged and Percy getting a birthday visit and gift from his father Poseidon. But it really just doesn't cut it. Thankfully, he makes up for it with the next book.