Half a life is not worth living.

Probably not a good idea to take advice from your dead twin sister. High school sophomore Trisha Traynor and friends have played the Halloween mirror game for years, the one that’s supposed to show a glimpse of the guy they’ll marry. But no one’s ever seen anything.

Until tonight—when Trisha is gob smacked by the candlelit arrival of her long-deceased twin sister, instead of her crush, Kirk Maxwell.

In a voice and vision that only Trisha can hear and see, Chessie claims to be back on a compassionate journey. Trisha fears she's gone nuthouse crazy. But she nonetheless follows the instructions Chessie outlines in their nightly conversations, until she finds herself stepping across some ethical lines, and probably ending all chances with Kirk.

When a sisterly showdown ensues, resulting in the shattering of the mirror, Chessie’s gone again, and a heartsick Trisha sets about righting her recent wrongs. That is, until she stumbles upon the real reason Chessie had come back and the most important glimpse yet that the mirror could never predict.