The title of this First Cut documentary refers to a person under a train on London's underground. Lucy Bennett's film introduces us to Debbie, whose husband threw himself in front of a train one morning, before going on to consider the effects of these suicides on those involved. A coroner explains that about half of those who attempt suicide in this manner will survive, although often with life-changing injuries. And drivers tell of their initial reactions, the trauma of attending the inquest, and how the nightmares never go away.