Enter the megadungeon! When the mysterious Gauntlight, an eerie landlocked lighthouse, glows with baleful light, the people of Otari know something terrible is beginning. The town's newest heroes must venture into the ruins around the lighthouse—and delve the dungeon levels far beneath it—to discover the evil the Gauntlight heralds. Hideous monsters, deadly traps, and mysterious ghosts all await the heroes who dare to enter the sprawling megadungeon called the Abomination Vaults! "Ruins of Gauntlight" is a Pathfinder adventure for four 1st-level characters. This adventure begins the Abomination Vaults Adventure Path, a three-part, monthly campaign in which the heroes explore a sprawling megadungeon to stop an ancient evil from renewing her monstrous vengeance. This adventure also includes an extensive gazetteer of the town of Otari, the heroes' home base, as well as new monsters, new rules, and new artifacts—including the dread Gauntlight itself!