- This article is about the episode. For the monster, see Harbinger.
Robert Jekyll discovers he carries a family secret which leads him into a web of intrigue.
It's 1885 and Edward Hyde gets into an altercation in the street with his patron, Sir Danvers Carew – and murders him. Fast forward to 1935, in Ceylon, where Hyde's grandson, the orphaned Robert Jekyll, is a young doctor and completely unaware of his ancestry. Here Robert saves a young girl with a superhuman show of strength. This strength is a side effect of his mysterious "condition", for which he has always taken pills. But this time the incident gets into the newspapers. The report reveals his whereabouts to a lawyer, one Max Utterson in London. So, Utterson summons Jekyll to England and Robert learns he is the sole heir to a large estate. There's only one snag, Robert wants nothing to do with the dark story.
However, Robert has also been spotted on the radar by two other organisations. The first is MIO, a government department headed up by Mr. Bulstrode. MIO's mission is to combat monsters. For them Robert's appearance is a harbinger of increasing enemy action. Tenebrae are the enemy: an ancient and sinister organizaion with a keen interest in recruiting shape-shifters like Robert. Sure enough Tenebrae and their top agent, Captain Dance, arrive in Ceylon and descends upon Robert's family.
Now Robert is adrift in London, with only Utterson and a new friend, Lily, to guide him. At which point news of event's with his foster family reaches him. Right now, right when he needs them most, Robert discovers his pills are missing and he suffers his first full blown transformation into another personality - Hyde. In contrast to the sensitive, considerate Robert Jekyll, Hyde is a selfish, uninhibited, muscle-bound brute. He goes out on the town looking for trouble, and finds it. At "The Empire" bar, an old watering hole of Edward Hyde's, Robert's drunken antics start a fight and he gets injured. An old man called Garson and the lovely bar owner, Bella, save his life.
- Tom Bateman - Robert Jekyll / Hyde
- Stephanie Hyam - Lily Clarke
- Natalie Gumede - Bella Charming
- Richard E. Grant - Roger Bulstrode
- Donald Sumpter - Garson
- Christian McKay - Max Utterson
- Melanie Wilder - Young Woman at Window
- Robin Hooper - Sir Danvers Carew
- Thomas Coombes - Edward Hyde
- Angus Wright - Gabriel Utterson
- Ace Bhatti - Doctor Vishal Najaran
- Lolita Chakrabarti - Gurinder Najaran
- Kasuni Narmada Kurulugama - Small Girl in Clinic
- Ruby Bentall - Hilary Barnstaple
- Raja Ganeshan - Postman
- Nathaly Nanayakkara - Beggar
- Dee Tails - The Harbinger
- Phil McKee - Hannigan
- Oliver Gilbert - Mister Wax
- Carl McCrystal - 1st Thug
- David Bark-Jones - Henry Jekyll
- Amit Shah - Brannigan
- Tom Rhys Harries - Sackler
- Rhys Isaac-Jones - Bellboy
- Robert Wilfort - Hotel Manager
- Amy Bowden - Adelie
- "Your secret's safe within my heart, and my heart belongs to you, darling." —Sackler
- "The secrets that you learn here will stay locked inside your head. You breathe one word outside this room, and BANG! BANG! BANG! You're dead." —Roger Bulstrode
- "It's only that I'm so confused and unsettled by this trip to England. The idea that I might find my real father. Who is he? Who am I? I don't know anymore." — Robert Jekyll
|"The Harbinger" • "Mr Hyde" • "The Cutter" • "The Calyx" • "Black Dog" • "Spring-Heeled Jack • "The Reaper" • "Moroii" • "The Incubus" • "The Heart of Lord Trash"|