Vengeance is Mine

Messages passed to a policeman in hospice care. Apocalyptic tales found in notes in his room. Is Macleod losing his mind as well as his health, or is there one last hurrah for a familiar foe?
When Seoras Macleod believes he sees an horrific figure from the recent past he puts it down to a state of PTSD. But when the evidence at his care facility seems to confirm the visits of a recent killer, he cannot shake off the feeling that he is being warned of a disaster of the murderer's making. Will the team trust their old mentor when he seems to be losing his mind?
With old age comes wisdom, and not a little insanity!