Stabbed to death while they slept, the killings of David and Elaine Lerner prove a mystery to DS Devlin and DS Brooks. Universally loved, there's not a single lead that points to grievances held or enemies made. As our Crown Prosecutors navigate this seemingly senseless crime, Jake's old mentor, Margaret Rumsfield, argues the accused should face only manslaughter charges. Without motive, without intent, can the CPS make a murder charge stick?