Cronc took the map as payment for a previous job. Supposedly it shows the location of an oil drilling platform off of the California coast. Legend has it the platform is submerged, but the map has the codes that need to be entered into a terminal to raise it. The platform was designed to provide for all of the needs of its inhabitants.
Cronc is the only character who currently knows about the map’s existence. He has it hidden in a… creative place.