The episode tells the arrival of Merlin (Colin Morgan) as a young man in Camelot, where magic is banned by King Uther Pendragon (Anthony Head).

In Camelot, he meets Uther's heir, the arrogant Prince Arthur (Bradley James), as well as Lady Morgana (Katie McGrath) and her handmaid, Guinevere (Angel Coulby).

As a witch (Eve Myles) plans revenge on the King's heir for the execution of her son, Merlin is informed by a cryptic dragon (John Hurt) that his destiny is to protect Arthur.

Merlin was conceived by Julian Murphy and Johnny Capps to be an origin story for the characters of the Arthurian legends, with family-centered entertainment.

Critical reception was mixed, with some feeling the show had promise but lacked imagination, and the actual plot of "The Dragon's Call" was deemed slight.

Merlin (Colin Morgan), a young sorcerer, arrives in Camelot just in time to witness the execution of Thomas Collins, a man accused of sorcery, by the order of King Uther Pendragon (Anthony Head), who has banned the practice of magic in his kingdom on pain of death.

As soon as the man is beheaded, Uther declares to the watching crowd that he shall throw a festival to celebrate twenty years since he wiped out magic and magicians from the kingdom.

The King's ward, Morgana (Katie McGrath), warns that Uther may be making enemies through his hatred and radical methods of wiping out magic.

Hearing the same voice calling his name that night, Merlin follows it to a cave where a dragon (John Hurt) informs him that he is destined to protect Arthur with his powers.

[3][4] As the Arthurian legends do not reflect genuine historical events, not being set in any one singular period in time, the show's creators were more interested in conveying a world that felt "real".

[5] Not constrained by historical accuracy, they had many opportunities to build the world in which they set their series; for example, tomatoes were included despite being absent from Europe in the Medieval era, and there was never a dragon in the earliest texts involving Merlin.

[6] The series was intended to have an "epic scale" that would have a wide "cross-generational" appeal; films such as Raiders of the Lost Ark were cited as inspiration.

[6] Looking back at "The Dragon's Call", Murphy and Capps felt that it had so much to introduce in terms of world and characters that there was not enough of the main plot of the episode.

[6] Eve Myles guest stars in "The Dragon's Call" as the villain Mary Collins and her host body Lady Helen.

[6] The cell Merlin is imprisoned in and the banquet hall at the end were both filmed in English stately homes, with real medieval architecture.

Overnight ratings showed that the episode had been watched by 6.65 million viewers live, a 30% audience share,[9] placing Merlin second for the night behind ITV's The X-Factor.

[14] Daniel Martin of the same paper felt that the series had potential, though "The Dragon's Call" had "awful dialogue" and was "a flimsy caper memorable only for centring around the wonderful big-eyed Eve Myles".

[16] Alessandra Stanley, reviewing for The New York Times, was pleased with the diversity of the cast and the chemistry between Morgan and James, though she felt it "would be better if its creators had taken more liberties and shown more imagination in coloring in the background of their young hero's world".

[17] Metro gave the episode three out of five stars, writing that "Colin Morgan makes a likeable boy wizard but there’s a bit too much formula – and not in the magical sense".

[18] The review described the episode as a "test of patience" due to Merlin's inability to use magic and the "hideously jaunty, distinctly non-medieval soundtrack".

[18] Tom Shales of The Washington Post criticised the "sluggish pace" of the premiere, noting that the episode was only "brightened" by the dragon, though similar creatures were common in the genre and it "lacks personality as well as panache".

[19] Den of Geek reviewer Mark Pickavance felt that the episode was "uneven and often very stilted", and failed at introducing both the characters and telling the story of the first meeting of Arthur and Merlin.

[13] The Times's AA Gill described Merlin as "bland", writing that it was for "a large untapped audience that yearns for Abercrombie & Fitch drama".

[20] Hermione Eyre of The Independent called it "horrible", disliking the "modern" feeling, the "awful" make-up, and commented that "Guinevere looks like a supply teacher".