Episode1-TheEternityRing　　MI5suspectsBritishatomicresearchhasbeeninfiltrated,andaskFoyletoinvestigatewhetheraRussianspynetworkcouldbeatworkintheheartofLondon.　　Episode2-TheCage　　Foyle’sinvestigationintothedeathofanamelessRussianleadstoamysteriousmilitaryfacilityandthediscoverythatthevictimwasaspywithdangerousconnectionstoBritishintelligence.　　Episode3-Sunflower　　ProfessorPeterVanHarengivesalecturetoagroupofstudentsontheself-portraitsoftheartistRembrandtandcausesayoungmantosufferafrighteningflashbackwhichendsintragedy.