A ghost story with a twenties setting and Rebecca Hall from Vicky Christina Barcelona.
Plot-wise, it's that one again: the one that starts with the uncompromisingly rationalist ghostbuster disrupting a fake seance, then shows them going to a spooky old pile on their next case in the same confrontational frame of mind, only to have their certainties overturned after a few encounters with the other world, before a poignant resolution reveals a) their own personal involvement in the hauntings, and b) the fact that some of the people they had been interacting with throughout were in fact ghosts from the start.
It probably wasn't all that original when James Herbert wrote it up as Haunted 25-odd years ago, and a lot of M. Night Shyamalan has flowed under the bridge since then. (The film they made of Haunted with Kate Beckinsale was even more similar, being set, unlike the novel, in the twenties too.) This one's by Stephen Volk, still plugging away; the usual meticulously maintained period atmosphere and settings knowingly undermined by proudly deliberate anachronisms of characterisation and dialogue, a few good scares, and a made for television look to it.