- Ep: 14
- The Curse of Cornelius Sigan
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Simon Nehan (Tom), Bradley James (Arthur), Colin Morgan (Merlin), Richard Wilson (Gaius), Anthony Head (Uther Pendragon), Mackenzie Crook (Cedric), Katie McGrath (Morgana), Angel Coulby (Gwen), Luke Neal (Sir Geraint)
- Written By: Julian Jones
- Directed By: David Moore
- Ep: 15
- The Once and Future Queen
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Fintan McKeown (King Odin), Jack Sandle (Kelda), Adrian Lester (Myror), Bradley James (Arthur), Colin Morgan (Merlin), Rupert Young (Sir Leon), Anthony Head (Uther Pendragon), Angel Coulby (Gwen), Alex Price (William), Richard Wilson (Gaius), Jai Armstrong (Guard No. 1), Mike Goddenough (Fyren), Katie McGrath (Morgana)
- Written By: Howard Overman
- Directed By: Jeremy Webb
- Ep: 16
- The Nightmare Begins
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Katie McGrath (Morgana), Angel Coulby (Gwen), Colin Morgan (Merlin), Anthony Head (Uther Pendragon), Bradley James (Arthur), Richard Wilson (Gaius), Rupert Young (Sir Leon), Beth Cordingly (Forridel), Colin Salmon (Aglain), Asa Butterfield (Mordred)
- Written By: Ben Vanstone
- Directed By: Jeremy Webb
- Ep: 17
- Lancelot and Guinevere
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Bradley James (Arthur), Katie McGrath (Morgana), Justin Avoth (Sir Robert), Angel Coulby (Gwen), Colin Morgan (Merlin), Michael Nardone (Kendrick), Michael Ballard (Bandit), Anthony Head (Uther Pendragon), Richard Wilson (Gaius), James Cosmo (Hengist), Santiago Cabrera (Lancelot)
- Written By: Howard Overman
- Directed By: David Moore
- Ep: 18
- Beauty and the Beast, Part One
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Adam Godley (Jonas), Sarah Parish (Lady Catrina), Richard Wilson (Gaius), Colin Morgan (Merlin), Anthony Head (Uther Pendragon), Bradley James (Arthur), Katie McGrath (Morgana), Angel Coulby (Gwen), Rhys Rusbatch (Guard), Michael Cronin (Geoffrey of Monmouth)
- Written By: Howard Overman
- Directed By: David Moore
- Ep: 19
- Beauty and the Beast, Part Two
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Sarah Parish (Lady Catrina), Adam Godley (Jonas), Anthony Head (Uther Pendragon), Bradley James (Arthur), Richard Wilson (Gaius), Rupert Young (Sir Leon), Colin Morgan (Merlin), Angel Coulby (Gwen), Rhys Rusbatch (Guard), Brian Peck (Eldred), Michael Cronin (Geoffrey of Monmouth), Katie McGrath (Morgana)
- Written By: Ben Vanstone
- Directed By: Metin Hüseyin
- Ep: 20
- The Witchfinder
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Colin Morgan (Merlin), Victoria Finney (Cathryn), Anthony Head (Uther Pendragon), Bradley James (Arthur), Katie McGrath (Morgana), Richard Wilson (Gaius), Charles Dance (Aredian), Angel Coulby (Gwen), Katie Foster-Barnes (Beatrice), Amanda Fairbank Hynes (Annis), Samara MacLaren (Rowena), Rupert Young (Sir Leon), David Sterne (The Apothecary)
- Written By: Jake Michie
- Directed By: Jeremy Webb
- Ep: 21
- The Sins of the Father
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Emilia Fox (Morgause), Anthony Head (Uther Pendragon), Bradley James (Arthur), Katie McGrath (Morgana), Richard Wilson (Gaius), Angel Coulby (Gwen), Colin Morgan (Merlin), Michael Cronin (Geoffrey of Monmouth), Alice Patten (Ygraine), Rhys Rusbatch (Guard), Rupert Young (Sir Leon)
- Written By: Howard Overman
- Directed By: Metin Hüseyin
- Ep: 22
- The Lady of the Lake
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Richard Ridings (Halig), Laura Donnelly (Freya), Richard Wilson (Gaius), Colin Morgan (Merlin), Bradley James (Arthur), Anthony Head (Uther Pendragon), Angel Coulby (Gwen)
- Written By: Julian Jones
- Directed By: Metin Hüseyin
- Ep: 23
- Sweet Dreams
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Bradley James (Arthur), Anthony Head (Uther Pendragon), David Schofield (King Alined), Kevin Eldon (Trickler), Mark Lewis Jones (King Olaf), Georgia Moffett (Lady Vivian), Angel Coulby (Gwen), Colin Morgan (Merlin), Katie McGrath (Morgana), Richard Wilson (Gaius)
- Written By: Lucy Watkins
- Directed By: Alice Troughton
- Ep: 24
- The Witch's Quickening
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Jonathan Bryan (Sir Radnor), Joseph Mawle (Alvarr), Emily Beecham (Emmyria), Asa Butterfield (Mordred), Chris McGill (Guard), Colin Morgan (Merlin), Katie McGrath (Morgana), Bradley James (Arthur), Richard Wilson (Gaius), Anthony Head (Uther Pendragon), Angel Coulby (Gwen)
- Written By: Jake Michie
- Directed By: Alice Troughton
- Ep: 25
- The Fires of Idirsholas
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Emilia Fox (Morgause), Jem Wall (Joseph), Anthony Head (Uther Pendragon), Richard Wilson (Gaius), Bradley James (Arthur), Colin Morgan (Merlin), Katie McGrath (Morgana), Angel Coulby (Gwen), Rupert Young (Sir Leon)
- Written By: Julian Jones
- Directed By: Jeremy Webb
- Ep: 26
- The Last Dragonlord
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Bradley James (Arthur), Richard Wilson (Gaius), Angel Coulby (Gwen), Colin Morgan (Merlin), Rupert Young (Sir Leon), Anthony Head (Uther Pendragon), Jonathan Coyne (Asgerd), Alexander Delamere (Innkeeper), John Lynch (Balinor)
- Written By: Julian Jones
- Directed By: Jeremy Webb
| Colin Morgan .............................. Merlin |
| Angel Coulby ................................ Gwen |
| Bradley James ............ Prince Arthur Pendragon |
| Katie McGrath ............................ Morgana |
| Anthony Head ................ King Uther Pendragon |
| Richard Wilson ............................. Gaius |
| John Hurt .......... The Voice of the Great Dragon |
