Dr Nikki Alexander and the team at the Lyell Centre solve five more thrilling mysteries. Returning for its 23rd series, Silent Witness is the world's longest-running crime drama currently on air, and continues to win huge audiences and praise from critics.A body in the concrete pillar of a car park. A downed plane. Scientific research gone wrong. The cases that end up at the Lyell Centre are rarely straightforward. Initial suspicions are challenged as the evidence mounts, and Nikki and the team must work harder than ever to find the truth