CadenaTres 28 presenta ; una producción de Argos Communications, Quality Films ; originally produced by Cadena Tres 28 ; historia original, Epigmenio Ibarra y Laura Sosa
a Hartswood Films production for BBC Wales in co-production with Masterpiece ; co-created by Mark Gatiss & Steven Moffat ; written by Mark Gatiss, Steven Moffat and Steve Thompson ; series producer Sue Vertue ; executive producers Beryl Vertue, Steven Moffat, Mark Gatiss, Bethan Jones ; directed by Jeremy Lovering, Colm McCarthy, Nick Hurran
Spring Creek Productions ; Sony Pictures Television ; produced by Peter McAleese, Elizabeth Chandler ; teleplay by Anne Meredith and Elizabeth Chandler ; directed by Roger Young