VIDEO : 'Counterpart' Finale On Sunday!

As Counterpart, the Starz spy-fi drama starring J.K. Simmons hurtles toward its season one finale on Sunday, there are several open plot threads that must be resolved. Showrunner Justin Marks also will need to set the stage for the previously announced second season of the dual universe thriller that has quickly become a critical favorite. Ahead of Sunday's season finale, here's a primer on what you need to know if you're just coming to the series now.