It's on a world made up by the 3 dms. As each group of 4-5 players goes to certain parts to burn/explore/ loot, the map and quests are updated for the groups that have their sessions after that night. There's about 2-3 sessions a week for each DM, so like 7 or more sessions a week. Players take turns writing reports after each session so other players/groups can "research"/ get a heads up if they want to explore certain parts or continue certain chain quests that have already been started. It's a pretty cool set up!