At Ballintoy Harbour in Co Antrim some strangers are trying to recall the name of a minor character from a minor scene in Game of Thrones. "Hotpie," Kristina Kurinska cries out to the strangers. "The little round guy." She instantly gets embarrassed. "I couldn't help myself. I shouted it out and then I felt like going into my turtle shell."

Kristina is from Slovakia but is au-pairing in Kildare. She's probably the biggest Game of Thrones fan on the McComb's Coaches Game of Thrones tour. She's here with her Swedish friend, Kim Svenson, who she met on a Game of Thrones message board. She can speak Dothraki, a language devised for the show. "Sek qoy qoyi," she says, which means "blood of my blood". "Shekh ma shieraki anni" is a Dothraki endearment that translates as "my sun and stars". Students of Dothraki do not start by learning how to ask directions to a train station or how to order coffee.

Game of Thrones, which has a passionate fanbase, is shot in Northern Ireland. Thus, a whole selection of location tours have sprouted up, one of which is guided by Game of Thrones fanatic Philip McComb. Today he leads a bus filled with twenty- and thirtysomethings from around the world. Unlike ordinary coach tours, it starts with a spoiler alert. "I have to assume everyone has seen up to season four," says McComb.

This isn’t entirely true. Hungarian couple Kornel and Kristina Simon are here for the scenery, while Toronto-born Yvonne Blackstock and Angela Szczepaniaka were only recently forced by their sister Wanda Fitzpatrick “to watch at gunpoint”. Mahn Levant from France just completed the first season. “But I have friends who won’t stop talking about it, so I know what’s going to happen anyway.” The rest of the group seem to be completists who have the books and have watched the whole series, although none of them fit old-fashioned stereotypes of nerd-dom.

"It's cool now to be into this stuff," says Cerwyn Sutherland from New Zealand.

“So I’m cool now?” I say.

“No you’re not,” says the photographer firmly.

Informed confidentiality

McComb cultivates an air of informed confidentiality. He refers to Game of Thrones show-runners David Benioff and DB Weiss as "David and Dan" and teases us with on-set trivia and future plot developments. "You only think there are seven kingdoms? Oh. Let's just say the map is not complete." "You think [that character] is dead? Interesting." The seventh book is already written, he says. He has this on good authority.

McComb is very likeable. He mixes local historical lore with pop-cultural knowledge and humour. The journey is worth it for the landscape alone, which nearly everyone finds remarkably beautiful (“It’s okay,” says Rob Grindy, who lives in the Lake District).

When we arrive at Game of Thrones locations, for copyright reasons McComb is unable to show us footage from the show. But sometimes when he gets to those places, he says, he likes to reminisce and look at scenes on his iPad, "and if by chance you're looking at the same time, well then, that's just coincidence".

The first location, Magheramorne quarry, site of Castle Black, home of the Knight’s Watch, is a restricted set. Buses are not allowed stop here, but there is, says McComb, “the strangest Bermuda triangle-like phenomenon whereby buses lose power as they drive by and slow down.”

Everyone tries to take photographs of Castle Black as this phenomenon takes hold. “Aaagh, trees,” complains young French accountant Nicholas Robert as his view is blocked. “That was too fast,” he says, shaking his head.

We drive on to Larne, once an exporter of “slaves and porcelain axe heads. They currently worship the god of Burger King,” says McComb, as we pass a crown-shaped effigy.

McComb has plenty of thoughts, some tongue-in-cheek, on possible links between Irish history and mythology and Game of Thrones. Daenerys Targaryen, he says, as we pass Mount Slemish, is based on St Patrick. "Think about it," he says, before outlining the pair's slave-, dragon- and snake-filled life stories. Mount Slemish, incidentally, is both the place where Patrick was enslaved and a location for the Dothraki grasslands.

Our next stop is at the Cushendun Caves, where “Melisandre gave birth to a shadow assassin”.

“That’s a scene in which a naked woman gives birth to a demon,” I observe.

“And nobody batted an eye,” says New Zealander Sacha Dick.

“Culture really is getting more violent,” says Cerwyn Sutherland.

“My dad walked in once when I was watching, just as a guy was getting his head crushed,” says Stephanie Teed, sister of Christie, whose birthday it is. “He said: ‘Why are you watching this?’” Stephanie’s favourite character is the sadistic King Joffrey, and she likes that the show feels like real history.

“But it’s not real history,” says Christie.

“I know,” says Stephanie and laughs. “But it feels like it could be real. I liked Harry Potter too.”

Soon we’re back on the bus negotiating a treacherous-looking cliffside road. Some people start nodding off.

“Guys. Guys. Put on your seatbelts. The road’s disappearing,” cries McComb.

Everyone wakes up with a start and starts feeling around for seatbelts.

“Only joking,” says McComb. Later he nearly falls out the door of the bus. “I think Paul [the bus driver] is getting sick of me,” he says.

Larrybane Quarry is the site of Renly Baratheon’s camp in season two. There McComb and Paul don warrior costumes and produce life-sized cut-outs of Tyrion, Arya Stark and Joffrey. The costumes, McComb says, are as close to costumes from the show “as HBO will permit”. People goof around, posing for photos with the cut-outs and warriors.

"Interview her," says Nicholas Robert, holding the cut-out of Arya in my direction. Robert is here with his brother Sebastian and girlfriend Marie Lenonnier. Sebastian says that Game of Thrones "is a mirror on society".

At Ballintoy, Dothraki tents can be seen in a field in the distance where scenes from season five are being filmed. We walk through beautiful countryside down to Ballintoy harbour, the location used for the Iron Islands, where Theon Greyjoy was baptised in the sea. There’s a big picture of Theon there.

“They’ve officially given in to globalisation and commercialisation,” chuckles McComb.

Then he offers to baptise us. “I’m a qualified priest of the Drowned God,” he explains.

Everyone makes excuses.

“It might ruin my hair,” says Cerwyn Sutherland. “So maybe not.”

“I actually worship the old Gods,” says Kristina Kurinska, referring of course, to the ancient religion practised by the Stark family.

McComb chats to me about the appeal of Game of Thrones and fantasy in general. He thinks the genre deals with real-world issues while also providing an escape. He's going to learn Dothraki and High Valyrian and he is to be an extra in the next series. "I even have a line," he says.

“What is it?” asks Kurinska.

“Probably ‘please don’t kill me’,” says McComb.

Built by giants

We then visit the Giant’s Causeway, which is not in the show but was built by giants. Then it’s on to the sinister-looking Dark Hedges, the strange serpentine beech-lined avenue down which Arya travels in the final scene of the first season. It was planted in the 18th century and is the only location specifically requested by David and Dan. “Three days preparing for eight seconds,” says McComb.

Our progress is hindered by a kilt-wearing wedding party having photos taken in the middle of the road. The photographer is trying to capture the group jumping with joy, but none can do it at the same time.

“Watching the Scots trying to jump, you understand why they’re terrible at sports,” sighs McComb.

When we eventually park, more high jinks are had along the Dark Hedges with cut-out characters and costumes. Nicholas Robert is wandering about dressed like Jon Snow. Theng Lim from Australia dons a Marjorie Tyrell-style dress.

“Be sure to mention that they were talking about knocking these trees maybe 10 years ago,” says Karen Cooper, one of the only Irish people on the tour. She is here with her sister and their niece. “We’ve a lot of natural beauty but don’t appreciate it . . . HBO saved this.”

On the way back to Belfast, McComb continues delivering factoids about production – about how there are six versions of Joffrey’s crossbow, for example, and how Sean Bean had an illicit cigarette pouch in his costume. At one point he asks a quiz question: “What character had his maester’s chains taken off him for dabbling in necromancy?” Kurinska quickly answers – correctly – “Qyburn”. The prize is some highly secret information about the production, which she spends a bit of time perusing. I ask what it was and she mimes zipping her lip. She looks happy.

“This is really cool,” she says. “Meeting people who are like-minded. You don’t feel alone any more.”

Patrick Freyne travelled courtesy of railtoursireland.com

Series concluded

WHISTLE-STOP TOUR: THE BEST AND WORST BITS

• Ate: Irish stew and soda bread at the Fullerton Arms in Ballintoy.
• Saw: The amazing Antrim coastline, parts of the fictional lands of Westeros and Essos, and Game of Thrones fans becoming very excited.
• Loved: the Antrim coastline, endearing enthusiasm, the sunshine and our guide's sense of humour.
• Hated: The fact we couldn't stop at certain locations. The inevitable bus fatigue. Joffrey (although he's a fictional character so I'm not sure he counts).
• Would I do it again? Yes, but ideally with an enthusiastic George RR Martin fan.