Probably unfulfilling to most horror fans who are expecting the standard formula, but in terms of delivering a thought-provoking message I’d say this is best one.

What Assayas is doing is drawing parallels between different levels of reality vs the invisible. There’s the main theme of real people vs ghosts, but at the same time there’s the theme of real social connections (Maureen & her sister in law) vs electronic connections (Maureen and her mystery texter). There’s also the theme of Maureen constantly trying to find connections with “ghosts” in history: Victor Hugo, Klint, whose lives become real to her even though these people are long dead. Or how about the weird connection Maureen has with her boss Kyra, notice how they never speak directly, it’s always through messages, making their relationship just as intangible as any ghost.

This isn’t a ghost story literally (although in a bold move he shows us that ghosts do exist), but it’s a powerful commentary on how human society is evolving toward a ghostly existence, for better or worse. We ourselves have become ghosts in the machine--the machine being our smartphones. It’s a pretty heady subject, and yet the movie is never dry or pretentious because the suspense is brilliantly done.