The setting is contemporary, judging by the automobiles, but the ambience is decidedly 1950's era spy film noir. As for genre, I'm forced to call Counterpart science fiction, in that it involves parallel universes, but it's really like nothing else within that genre.

The general scenario is this: 30 years ago, for reasons unknown, reality split into two bifurcating, independent time lines. Until that point, all was unified, meaning that every character alive at that point shared identical histories. Now, things have begun to diverge. But there is a doorway between the universes in a building in Berlin.

Again, for reasons unknown, the two sides have been both communicating with, and spying on, one another through this doorway, and this is where our protagonist Howard Silk (J.K. Simmons) comes in. "Our" Howard is a low level functionary in this spy agency who hasn't a clue as to what is really going on until, one day, his counterpart arrives with news that a woman from "their" side has been sent over to assassinate people on "our" side, including Howard's comatose wife. No one knows why, which is the prevailing state of awareness in this decidedly curious story. "Other" Howard decides that "our" Howard is critical to his investigation and, thus, the strange alliance begins.

J.K. Simmons is a phenomenal actor, despite often being cast in secondary roles, and Counterpart is truly his opportunity to shine. He plays a single character, but one with two separate backgrounds despite shared childhoods, a role requiring some subtlety and nuance. He plays both characters to perfection as the similarities and differences between the two create something of a broader character that calls into question our notions of identity.

In a way, Counterpart is an examination of the concept of self, or soul, but it is also an engaging mystery/thriller. Like its main character, the sum is both greater than, and equal to, its parts.