When a pregnant junior doctor, Alice Cullen, is found beaten to death in the car park of the hospital where she works, the prime suspect becomes her boyfriend, who cannot provide a solid alibi for where he was at the time of the killing. Mobile phone traces put him in the right place at approximately the right time, but when his therapist provides him with an alibi for that evening, DS Devlin and DS Brooks begin to suspect they are having an affair. On arrest, what initially seems like a crime of passion soon unravels into a conspiracy involving senior level government officials. Risking their careers and defying the instruction of the Director of Public Prosecutions, James and Alesha must get to the bottom of this case before another life is destroyed.

An unfolding tragedy takes unexpected twists and turns as what initially looks like a cot death of 6 month old Alex Raines is later diagnosed as shaken baby syndrome leaving Matt and Ronnie with a murder investigation on their hands. But with many possible suspects - the neglectful mum, the absent dad, the resentful nanny or her short-tempered soldier boyfriend - who should our cops arrest? During the trial and pitted against the indefatigable Helena Marsden, the very framework of this family is pulled apart and the CPS are forced to do some investigating of their own.