From the back of the book:
He's Back And He's Out For Blood
It should have been the end. When the bloodthirsty adventurers burst into his throne room and mercilessly cut him down, the tale of Merlokrep, last king of the ill-fated Truescale Tribe, should have ended. But the fates weren’t yet finished with the Kobold King, and now a dark power has brought him back from the dark beyond to wreak his vengeance upon those foolish adventurers who destroyed his tribe.
Revenge of the Kobold King is a dungeon-based adventure for 5th-level characters compatible with the world’s most popular roleplaying game. This takes your heroes back beneath the haunted trees of Darkmoon Wood and into an ancient Azlanti crypt in search of the all-too-familiar monsters that are brutally murdering the people of Falcon’s Hollow.
This adventure returns to Darkmoon Vale, an area of the Pathfinder Chronicles campaign setting first visited in D1: Crown of the Kobold King and E1: Carnival of Tears, and further detailed in the Guide to Darkmoon Vale.