Lucas used to delve dungeons. Now, he has to run one.
After Lucas dies during a freak explosion, divine intervention sees him brought back to life with the power to control a new dungeon.
There are just a couple of issues: his old body is bound to his dungeon, and the craziness of what he thought was his final act is only getting weirder. When he sees newbie adventurers entering his dungeon, though, he decides to help them survive and complete their quests. 
After all, adventuring is a process, and someone needs to guide the rookies.