Beware the spirits of Lake Manuxet...

"Don't look out towards Knob Island at night." That was the warning Douglas' grandfather gave him as a boy. Returning to the shores of Lake Manuxet as a grown man, with his twin sister and their ailing grandmother in tow for a final, nostalgic visit, Douglas begins to experience frightful things in his cherished childhood vacation spot.
Just what is it that claws its way out of the lake each night, only to approach their cabin? What mysteries does the remote lake hold? Are the horrors Douglas experiences genuine, or is he simply inheriting the madness that seems to run in his family? What is the true nature of the cryptic warning his grandfather gave him so many years ago about the small island at the center of Lake Manuxet?
What begins as a sentimental pilgrimage to a once-enjoyable vacation spot rapidly deteriorates into a fight for survival and sanity.