It’s autumn, 1987, and as a major arms control summit looms, Elizabeth is pushed to her limits as never before. Philip, meanwhile, has settled into running the newly expanded travel agency – until an unexpected visitor makes a disquieting request.

In the aftermath of a disastrous operation, Philip and Elizabeth clash about how to handle things with Paige. Stan struggles to contain the growing risks of Sofia and Gennadi's fraying relationship.

With the arms control summit under way, a shocking revelation from Philip throws Elizabeth - and her work - into turmoil. Stan follows a dangerous hunch.

Elizabeth wrestles with competing loyalties, and Philip has an encounter that turns into much more than he had bargained for.