Your holy mission to kill the degenerate baron has been fulfilled. You're standing over his corpse when the game starts. His subjects have already fled the castle and there ought to be no further obstacles. But as it turns out, his subjects have fled because they know the worst is yet to come.
Saying anything else about this game's plot threatens to ruin the core mechanic, which gradually reveals itself as you attempt to explore the castle. It's clever, but it's also a tad irritating. As the game closes in around you, your options diminish. This means it's very easy to waste time at the beginning, examining objects and rooms and whatnot, before you even realize that you're wasting time. When you do realize what's happening, it's probably too late.
The outcome leaves me conflicted. It's necessary to go into the game without preconceptions in order to get the most from the experience. However, this means that it will also likely punish you a few times until you learn to economize your puzzle-solving. The "optimal" good ending is also not as rewarding as the "normal" good ending, as though, after you've solved everything, the game is in a hurry to tidy up.
Nevertheless, it's well worth playing for the writing, mood, light humor, and the overall concept. Just be prepared to undo or restart.