Traces of blood on a Roman sword are linked to an unidentified, headless corpse found in 2008, Taking up the unsolved case, the team enters the world of Roman battle re-enactors. Just as Danny starts having feelings for someone new, he learns that his wife might be discharged from the secure hospital where she has spent several years.

When a teenage boy trrows a brick onto a busy highway, DNA on the brick provides a link to the killer in the 2010 murder of a 55 year old interpreter and chess enthusiast. Steve brings his dying father to a hospice in London.