Silent Witness

A severed finger is brought to the Lyell Centre by DCI Rory Goodchild and Immigration Enforcement Officer Pia Butler, who ask Nikki and Thomas to test for a DNA match with 17 year-old Syrian illegal immigrant Akka Khoury.

Akka was sent the finger by a people-smuggler who claims to have her mother, demanding money for her return. However, Akka quickly flees, giving Goodchild and Butler the slip.

Meanwhile, Akka's 12 year-old cousin Sosa is alone in a migrant camp in Northern France. There she meets Yusuf Hamed, a people smuggler, who puts her in a hidden compartment in a white van along other illegal immigrants on a cross-channel ferry to the UK.

Back in England, Yusuf and his smuggling partner Jamal realise one of their vans has disappeared, with a cargo of refugees inside. Has it been snatched by the police?

Later, when Nikki and Jack are called to examine the death of Jamal, who has died falling from the top of a building, Clarissa finds a sequence of numbers and letters on Jamal's phone and the team set out to crack the code.

A desperate and beaten Akka turns up at the Lyell Centre in need of medical attention. Nikki takes her to A&E but nurses soon become suspicious of Akka's status, so Nikki smuggles her out of the hospital and helps her to escape from the police. How will Nikki resolve the moral quandary of helping an illegal immigrant evade the law?

When Thomas suggests the code corresponds to a location marker on an A-Road, the Lyell team head into nearby woodland, finding Yusuf and Jamal's missing van…