What's Mine's Yours is a 4th edition Dungeons & Dragons adventure for 1st level characters.  This adventure begins in the marketplace in the town of Fort Wood, where the players are approached by representatives of the Guild, a Merchant collective heavily invested in mining operations.  They are escorted to a courtyard at the Guild headquarters in Fort Wood, where they are provided with the setting. Kobolds have taken control of a mine of great importance to the Guild.  Their task is to free the mine of the kobolds.  Over the course of the adventure, the party discovers there is a more sinister story surrounding the Guild's doings in the mine.

This adventure easily serves as the first adventure undertaken by a new party of 1st level characters.