While search for a break in the town's main waterline, Big Bill Hartley discovers a chunk of rich silver ore. He convinces an ambitious saloon girl to bankroll his mining operation and digs a shaft from an abandoned house to the pocket of silver that lies directly under Tombstone's main street. Just when Bill thinks he's struck in rich, the mine collapses, causing a girl riding on the street to be trapped inside the resulting sinkhole. (thetvdb.com)