From the publisher's website:
A Pathfinder Society Scenario designed for 1st level characters.
You venture for the first time into the massive haunted dungeons beneath an abandoned siege tower in the deadly Cairnlands, where you will experience firsthand the true dangers of being a tomb-delving Pathfinder.
This scenario is designed for play in Pathfinder Society Organized Play, but can easily be adapted for use with any world. This scenario is compliant with the Open Game License (OGL) and is suitable for use with the Pathfinder Roleplaying Game.
To Delve the Dungeon Deep is part two of the three-part First Steps campaign arc, designed specifically for 1st level characters as an introduction into the Pathfinder Society Organized Play. It is the sequel to Pathfinder Society Scenario Intro 1: First Steps-Part I: In Service to Lore and is followed by Pathfinder Society Scenario Intro 3: First Steps-Part III: A Vision of Betrayal. These scenarios are available as a free download from the publisher.