This was a polarizing one for even die hard fans of Del Toro. I enjoyed it for what it was and not what I wanted it to be but your mileage may vary.
A young woman who knows a thing or two about ghosts (having seen her own mother return as one when she was a child) falls in love with the Baron of a remote estate. Despite her father's objections (eventually silenced by a brutal murder), she marries the Baron and moves with him to Europe. Their mansion has a giant hole in the roof and the ground bleeds red clay. The old house is full of secrets and ghosts but really, as the protagonist herself says, this is a story with ghosts and not a ghost story.
Mia Wasikowski as the main protagonist does a fan job despite acting against Tom HIddleston and Jessica Chastain (both of whom bring their A games). The ghost designs are compelling but they actually hurt another Del Toro movie in retrospect. In The Devil's Backbone, the main ghost of a little drowned boy looks like he is always underwater. In Crimson Peak, all the ghosts look like they are underwater whether they died in water or not. That's apparently just how Del Toro wants to see his ghosts.
At any rate, the gothic romance outstrips the horror here but the resolution is sufficiently bloody to make most genre fans happy. For people expecting gore or even more hardcore horror, this may not be the movie for you.