Production listings seen by TV Zone suggest the fourth instalment of the hit drama is to commence filming this July in Devon.

　　该剧聚焦军情五处特工约翰·休斯（肖恩·埃文斯 Shaun Evans 饰）的双线挣扎：一边是危机四伏的任务，一边是濒临破碎的家庭。一场秘密会面，掀起无法回头的漩涡。压力如影随形，渗透工作、爱情与无处不在的注视之下。当猜忌蔓延、忠…