Wet Grandpa don't care to say much, but his brain is always running. (It was that way before, too). Mostly now it plays back his wife's freshly dead eyes and his own terrible drowning. Sadness and fear haunt his living corpse. In his dreams he reaches out and the water listens. In dreams (and unexamined thoughts) he needs others to be like him. And so the river thrashes landward.
Wet Grandpa is system neutral/D20 agnostic adventure for however many players you can gather together. In it they will seek dubious treasure, find a village on its last legs, and possibly avert a quite unnatural disaster.