As I recall, DARK SHADOW's final episode wrapped up its current storyline, but ended on a cliffhanger that was presumedly intended to launch a new storyline. The show dealt with this by adding a final voiceover along the lines of:
"But, for the first time in Collinswood's history, the marks on Carolyn's neck were
just caused by an animal. She soon recovered and everybody lived happily ever after, no longer haunted by . . . Dark Shadows."
(I'm paraphrasing from memory here, but that was the gist of it!)