Berlin Station posits a mole in the CIA's Berlin Station who is feeding leaks to the media. The CIA sends in an operative under cover to expose the mole and, through a tumultuous ten episodes, the mole is unmasked.
The series was filmed in Berlin, and the location shots are great. A real Valentine to a gritty, interesting city. The actors, too, are all quite good and the dialogue was often very good as well.
Unfortunately, there are some bizarre continuity problems which were blindingly obvious. For instance, the mole gets access early on to the undercover agent's cell phone and can use it to hear everything that's going on within range of the phone - except when it can't. Or, a terrorist has taken a CIA agent hostage with the help of two thugs, one of whom is killed and the other of whom just isn't there when they burst in on the terrorist and the hostage.
Nonetheless, definitely worth a watch and will probably watch series 2 when the opportunity arises.