Caroline and Will take on a last-minute prosecution case, only to find that the system has conspired to make it almost impossible to win.

Faced with an elderly skittish victim who just wants it all to be over, and an underfunded chaotic system that thwarts them at every turn, Caroline and Will ride their luck alongside a harassed CPS and an unhelpful volunteer, in a wacky race to bring a thug to justice.

Meanwhile the pupils' competition heats up, and Liam and Danielle find incriminating evidence against Pia. Things get figuratively and literally dirty. Will, still juggling the deceit in his personal life, wants no part of it. But, in this world, who can afford to be an idealist?