On their way to celebrate the wedding of First Officer Will Riker and Counselor Deanna Troi, Captain Jean-Luc Picard and the Enterprise crew are suddenly diverted for an unexpected diplomatic mission to the planet Romulus. Longtime enemies of the Federation, the Romulans have expressed their desire to initiate negotiations that will hopefully lead to a long-awaited unity in the galaxy. But upon their arrival on Romulus, the Enterprise crew is faced with a threat that could lead to the destruction of the planet Earth, and Picard comes face to face with a man who may prove to be his most dangerous adversary--yet a surprisingly personal nemesis.