As Philip (Nyman) travels around Britain debunking psychics, he gets a message from a mentor challenging him to investigate three unexplained cases. First is Tony (Whitehouse), a night watchman who had a ghostly encounter in an abandoned warehouse. Then there's the frazzled Simon (Lawther), who met a demon in the forest. And finally Mike (Freeman), who had a harrowing encounter on the night his wife gave birth to their daughter. As he investigates, Philip thinks all of these are simple to explain. But he's having some odd experiences of his own.

The script is fiendishly clever, dropping hints and suggestions everywhere. And it's orchestrated in an amusing way that keeps the audience off balance with sharp-edged humour while constantly unsettling us with creepy imagery and sounds. That said, the sound mix is rather pushy, using the usual musical cues and loud crashes to spike the atmosphere and deliver a cheap fright. Much more effective are the creeping moments of nastiness that are based more inventively on characters and situations.

It's also more involving because the actors remain naturalistic. The four leads are all excellent, men who perhaps don't quite realise that they're on the knife-edge of sanity. Nyman has the most challenging role as the sceptic grappling with his refusal to allow for the possibility of the supernatural. Lawther has the most colourful role as the jittery young Simon, while Whitehouse shines as the bitter, sardonic shell of a man. And Freeman has the most fun as an arrogant rich man who may have a screw loose.

Where this story goes is constantly surprising, as the script twists and turns its way through a series of revelations that merrily pull the rug out from under both the characters and the audience. The final act is almost exhilarating as it continually leaps in unexpected directions, bringing the story together in a way that's much more deeply disturbing than expected. Of course, this is so carefully assembled that we should have worked out the puzzle far earlier, but it's a lot more fun that we don't.

themes, language, violence

16.Jan.18