It's only as haunted as you are.

After two raids turn up zero evidence, narcotics detective Dwayne Spare infiltrates a crumbling apartment building where a suspected manufacturer of krokodil is hiding--but finds something much worse. The chemist Gerald Metzger isn't after money; he's lulling his most 'dedicated' customers into catatonia, to make contact with an eldritch being.

When Dwayne's cover is blown, he becomes Metzger's new test subject, an involuntary pilgrim into a world where "it's all just in your head" is far from a reassuring statement.