Plot summary
A summit to discuss letting Kosovo and Serbia join NATO is derailed when Spain rescinds its support because of sudden threats of independence for Catalonia. Internet claims that a large mass grave has been discovered in Kosovo raises tensions. More news stories inflame the populace of Kosovo and result in violence against Serbians. The US identifies a Russian-sponsored troll farm behind the onslaught of fake news stories and takes it down, then presents their intelligence to the representatives from Kosovo and Serbia to help them realize how they were being manipulated.
Blake uses a similar tactic (identifying a common enemy) to bring together two departments that had been unwilling to cooperate on a malaria prevention program. Henry has to file a report when Gordon comes to their house late at night in a delusional state, which results in the White House physician, who had given Gordon pills to help him sleep, being asked to resign.
Credits
Adapted from Wikipedia contributors, Madam Secretary season 5. HTML formatting and reference markers removed.