MBS - FPLE
This plugin makes your game a 3D labyrinth explorer, it's quite easy to use once everything is set up.
I've been working on this for some time now, I really hope you enjoy it (and I swear I'll try my best to fix all the issues you report >.<)...
I am adamant about not having missable quests, which means having to write entirely new scenes at each plot progression that takes into account that time and events have passed since the quest could first be accepted while still having there be a quest to solve in the first place. It's worth every second.