Be afraid, for here it is … again … emerging waxily from the darkness. This disturbing figure must surely be thousands of years old by now, a princeling worshipped as a god but entombed in his own riches and status; remarkably well preserved. It is Tom Cruise, who is back to launch a big summer reboot of The Mummy, that classic chiller about the revived corpse from ancient Egypt, from which the tomb door was last prised off in a trilogy of films between 1999 and 2008 with the lantern-jawed and rather forgotten Brendan Fraser in the lead. And before that, of course, there were classic versions with Boris Karloff and Christopher Lee both variously getting the all-over St John Ambulance treatment.

Traditionally, The Mummy is a scary movie (though unserious) about taboo and transgression, based on the made-up pop myth about the mummy’s “curse” – which has no basis in the history of ancient Egypt, but is a cheeky colonialist invention, which recasts local objection to our tomb-looting as something supernatural, malign and irrational.

Yet that is not what this Mummy is about. It brings in the usual element of sub-Spielberg gung-ho capers, but essentially sees The Mummy as a superhero origin movie; or possibly supervillain; or Batmanishly both. The supporting characters are clearly there to be brought back as superhero-repertory characters for any putative Mummy franchise, including one who may well be inspired by Two-Face from The Dark Knight.

This has some nice moments but is basically a mess, with various borrowings, including some mummified bits from An American Werewolf in London. The plot sags like an aeon-old decaying limb: a jumble of ideas and scenes from what look like different screenplay drafts. There are two separate ancient “tomb-sites” which have to be busted open: one in London and one in Iraq. (The London one, on the site of the Crossrail excavation, contains the remains of medieval knights identified as “crusaders” who have in their dead Brit mitts various strategically important jewels they have taken from Egyptians: who were subsequently buried in what is now Iraq. Erm, Egyptians in Iraq? Go figure. Perhaps it’s because they are evil and had to be taken out of the country, like CIA rendition of terror suspects.)

The Cruisemeister himself is left high and dry by plot lurches that trigger his boggle-eyed, WTF expression. In one scene, he is nude so we can see what undeniably great shape he’s in. The flabby, shapeless film itself doesn’t have his muscle-tone.

Midair acrobatics … Tom Cruise and Annabelle Wallis in The Mummy. Photograph: Allstar/Universal Pictures

Cruise plays Nick Morton, an adorable rascal in the Iraqi warzone who goes around in a TE Lawrence headdress stealing antiquities to sell; well, it’s that or let them be destroyed. He’s helped by his exasperated buddy Chris (Jake Johnson), while Nick has already seduced beautiful expert Jenny Halsey (Annabelle Wallis) who in spite of herself is entranced by Nick’s distinctive cherubic handsomeness. Then they blunder across the extraordinary tomb of evil Egyptian sorceress Ahmanet (Sofia Boutella) who has some kind of weirdo mind-meld experience with Nick. Her creepy spirit accompanies him back home where she is intent on getting that precious jewel to unlock her full power. Nick’s plane crashes, giving him the opportunity for some Mission: Impossible-type midair acrobatics, those gorgeous chops pulling some serious Gs.

Russell Crowe lumbers on at one stage, amply filling a three-piece suit, playing an archaeological expert and connoisseur of secret burial sites, who has some sinister connection with government agencies. Unlike Nick, he has no Indiana Jones-type heroism, and that formal attire of his signals that he does not have Nick’s kind of heroic looseness. He is a figure to be mistrusted, although when he reveals his name and his destiny, he is just a distraction – and silly.

In the end, having encouraged us to cheer for Tom Cruise as an all-around hero, the film tries to have it both ways and confer upon him some of the sepulchral glamour of evil, and he almost has something Lestat-ish or vampiric about him. Yet the film really won’t make up its mind. It’s a ragbag of action scenes which needed to be bandaged more tightly.