The emotional bookends of the episode-i.e. Dean's guilt around dad's death, visiting mom's grave-work and the save the episode somewhat from the clunky writing. Likewise, the commonness of the relationships at the center of the monster story grounds the creepiness in believable reality. Unfortunately, the coincidence of stumbling upon a case, and case that reflects Dean's struggle with grief, is too much to take. The script knows this and hangs a lantern on the coincidence. It is not enough as the plotting still feels contrived.
