A passenger dies bleeding on board a flight from Africa to London: the cause is believed to be the Ebola virus. Dr. Stephen Dunbar begins to investigate and discovers that the virus has nothing to do with it. Meanwhile, the number of victims of an unknown virus is growing rapidly. Politicians are trying to hush up this story, and scientists are trying to find the cause of this epidemic. Even Dr. Dunbar is at a dead end, but the truth, which gradually comes out, plunges everyone into horror and shock... “Joker” continues the series of medical thrillers by the world famous Scottish writer Ken McClure about the investigations of Dr. Stephen Dunbar, an investigator for particularly important cases of the secret agency “Sci-Med”. Inspectorate."