The Thing That Came In From The Fog

This Fallen London exceptional story is pretty good.

Fog has encroached on London, and out of it steps a bizarre foggy figure that walks around your house, using your stuff and playing chess a lot.

As you investigate this disturbance, you learn more about a cult and a conspiracy that draws in some of the strangest features of Fallen London: (mild spoiler) (Spoiler - click to show)unusual biology and the Elder continent. Emotionally, this game deals well with a certain kind of loss without becoming too maudlin.

Unlike most exceptional stories, this has some very different endings that can be hard to achieve. If you're really invested in one outcome and don't want to pay money for a reset, it's worth looking up or getting advice online.