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.