For those who felt shortchanged by Arnold Schwarzenegger’s non-action cameo in the 2004 Jackie Chan adventure yarn, Around the World in 80 Days, this similarly silly Chinese-Russian adventure yarn makes up for lost time by pitting the two ageing action stars against each other in the Tower of London. It’s a perfect setting, with both stars behaving in a complimentary and wholesome manner, with Arnie hamming it up as the Tower’s chief warden (not even attempting the British accent) and Chan playing his prisoner, a bearded and bedraggled kung fu mystic. They have a typically zany slapstick tussle involving swords and chains and banter aimed directly at their respective fanbases. To the film’s credit, it’s actually quite a nice sequence, if utterly meaningless, forming a small part of a much wider, convoluted story which should come with a guidebook.

The appearances of Chan and Schwarzenegger act as some kind of through-line, although their scenes never feel like anything other than an afterthought. It may be because this is actually a sequel to a 2014 Russian fantasy film called Viy, starring Jason Flemyng as 18th century cartographer, Jonathan Green, who travels through Transylvania and gets up to all sorts of havoc with magical creatures and beasties and such like. Flemyng, who is the film’s real star, returns as the plucky Green to map Russia’s eastern borders and, because this sequel has been bolstered by a chunk of Chinese change, it ends up looking like one of those indigestible, CGI-loaded, cross-cultural puddings like The Great Wall or Enter the Warrior’s Gate; a dazzling spectacle, yes, but completely weightless.

This is particularly evident in the final act, in which Flemyng all but exits the film and the action is handed over to an undercover Chinese princess (Helen Yao), who leads a retaliation against a royal imposter in a bid to free her people. The final battle includes a giant adversary made of rocks and a dragon. Yao is actually very good as the royal warrior, and Ma Li does a nice turn as a kick-ass witch, complete with lethal bladed fan. The final fight sequence is smartly arranged by action director, He Jun (alumni from the Jackie Chan Stunt Team), and in true co-production style, we even get to see a bit of Cossack kung fu dancing.

Chan’s buddy in the Tower appears to the ‘Man in the Iron Mask’ (hence the film’s UK title, The Iron Mask), which is revealed to be the Russian Emperor, Peter the Great, who is sprung from prison to join in the swashbuckling fun as a stowaway on board a ship in a sequence seemingly lifted from a Pirates of the Caribbean film. Then there are incredibly brief cameos from really good actors; people like Charles Dance and Rutger Hauer (in one of his final film roles), who stop by for a quick pay-check. The post-production job does the story no favours; some of the Americanised dubbing doesn’t quite align to the tone of the performances, even the quality of the audio varies throughout, and the film ends up being narrated by not one, not two, but three separate characters. Given its star power, you’re right to be curious; but at two hours, it’s an epic, unrelenting and head-scratching mess of a film.

AKA: The Dragon Seal; Journey to China: The Mystery of Iron Mask; The Mystery of the Dragon Seal; The Mystery of Dragon Seal: Journey to China; Tayna pechati drakona (original title); Viy 2.

The Iron Mask is available to watch on digital in the UK via Signature Entertainment.