Grimm is riveting because of its beautiful cast members, but it is severely hampered by its melodramatic, Peyton Place subplots. Its writers did not learn the main lesson from its template, Kolchak: The Night Stalker. Note that Night Stalker is a big success because it focuses completely on its main story per episode.

Subplots are red flags that indicate to the audience that the subject matter is not substantial enough to carry through an episode.