利用假日,医科大学女教授于胜男来到光华救济会为穷人们看病问诊,巡捕房探长钟朗来此探望胜男,结识了当年曾帮过胜男的救济会负责人佟叔叔。钟朗也借此机会为胜男引荐了对她父母一案内情有深入了解的人。因叛国罪羁押在法国人监狱中的端木岩闪烁其词,令前来问询的女儿胜男颇为懊恼。与此同时,和钟慧相识的难民苏老伯被人杀害,由此牵连出一个连续难民杀害事件。胜男从尸体中检验出神秘毒素,谁知却将灾祸引到了自己身上。钟朗及其搭档韩非介入调查,而线索竟和端木岩联系在一起。
一起隐藏着战争阴谋的黑幕慢慢浮现,钟朗他们面临前所未有的险恶对手……。The Roman Empire occupied Britannia (Britain) for four centuries, providing protection and peace in exchange for submission. The Romans built Hadrian's Wall on the northern border to keep out the Picts, fierce and mysterious warriors who painted them-selves blue. But in the fifth century, the Romans left, leaving the British to fend for themselves under the leadership ...。