Forensic pathologists Professor Leo Dalton Dr Harry Cunningham and Dr Nikki Alexander are back in one of the BBC's most successful and longest-running crime dramas. Series 11 kicks off with an RAF helicopter crashing into an asylum seekers' detention centre. Harry suspects a possible RAF whitewash and finds himself up against the Ministry of Defence who are struggling to cope with the demands of the wars in Iraq and Afghanistan. Subsequent stories include a trail of murders that leads to a hospital cover up and the killing of a notorious female murderer that forces Nikki to revisit an emotive and controversial case from her past. In Series 12 Leo arrested for drink driving and finding himself doing community service on a rough London estate where gang violence among kids is common. When Nikki investigates a murder of a young girl from the same estate Leo finds himself in the midst of a turf war. Elsewhere Harry mentors an eager medical student who seems more interested in the media frenzy over his latest case than pathology and Nikki investigates an armed raid on a terrorist cell facing increasing police hostility to her investigation as she begins to suspect the victims are innocent...