Seven years after defeating the mummy Imhotep (Arnold Vosloo), Rick (Brendan Fraser) and Evelyn O’Connell (Rachel Weisz) are dragged back into the action when forces working to resurrect Imhotep kidnap their six year-old son and take him to Egypt. Hot in pursuit, Rick and Evelyn race to prevent Imhotep and his servants from reviving the dreaded Scorpion King (Dwayne Johnson) and seizing control of the Army of Anubis.

The Mummy Returns is a lot of things. Ostensibly it is a 2001 sequel to the surprise 1999 hit The Mummy. It is also a textbook example of how to cripple a nascent movie franchise, a showcase of over-ambitious and woefully mishandled visual effects, an egregious abuse of popular Egyptian mythology, and more than anything else a stern lesson for Hollywood that rushing a film to meet a pre-determined release date will never end well.

Many of the ingredients that made the 1999 film a delight are retained. Brendan Fraser still plays his entertaining matinee idol role with warmth and humour. Oded Fehr still infuses the Medjai swordsman Ardeth Bey with gravitas and dignity, and a neat underlying lightness. Arnold Vosloo still gives the villainous Imhotep a strong, muscular edge. The orchestral score – Alan Silvestri replaces Jerry Goldsmith – continues to emphasise a classically old-fashioned atmosphere of stirring adventure. Beyond this the film really is all over the place.

The plot manages to be both overly complicated and weirdly arbitrary. It begins by introducing a new villain, the Scorpion King, in ancient Egypt. He tries to invade and fails miserably, and at the point of death while exiled to the desert he makes a bargain with Anubis to gain supernatural powers and control over a magical army of ferocious dog people. A quick note to the writers: the evil god they were looked for was Set, not Anubis, and even then he was a god of chaos rather than evil. Once the Scorpion King succeeds in his invasion, his soul is taken by Anubis and the dog army dissolves to sand. That’s the problem with deals with gods, I suppose; there’s always the pesky fine print. It should be noted that The Mummy Returns was Dwayne Johnson’s first significant dramatic role, following guest appearances on the TV shows The Net and Star Trek: Voyager, and his lack of experience at this early career stage is painfully clear.

Cut to 1933 and the O’Connells are now married with a son named Alex (Freddy Boath). Boath was nine when he shot The Mummy Returns, but his character can only be six given the timeline between first film and sequel. In the actor’s defence, he’s a far less risible than the typical kid sidekick in these sorts of films. That said, the character is still a painful irritant on the rest of the film. A more cleanly structured sequel might have allocated his story role – he gets irreparably attached to a bracelet that leads to the Scorpion King’s lair – to his mother Evelyn, which would have both removed the annoying child stereotype and given Rachel Weisz more material with which to work.

The O’Connells find the bracelet, Alex gets it attached to his wrist, Imhotep is raised by the reincarnation of his long-dead lover Anck-Su-Namun (Patricia Velasquez), Rick is revealed as a prophesied warrior of Egyptian legend, Evelyn is revealed as the reincarnation of the princess Nefertiri, everyone races to the fabled oasis of Ahm Shere, and Rick and Imhotep battle one another in a pyramid to defeat the revived Scorpion King and either control or dispel the Army of Anubis. It is a narrative mess, and shows a remarkably rushed and inattentive scripting process.

If the script feels rushed, it has nothing on the film’s visual effects. The Mummy Returns is an enormously ambitious film, with a CGI list of requirements that includes undead warriors, forests sprouting from deserts, zombie pygmies, thousands of dog warriors, and a climactic half-man half-scorpion monster. There is not a single visual effect in the film that does not look substandard and rushed. The Scorpion King in particular is an embarrassment to the whole film. Industrial Light and Magic famously begged Universal Pictures to delay the film’s release by six months so that they could do a proper job, but a fixed release date was considered more important than a decent film. It all but kills the film. One could possibly overcome the weak writing and flabby narrative if there were some dramatic and visually engaging action sequences and chases, but it all collapses to pieces.

It is an enormous shame. The 1999 Mummy presented a wonderfully entertaining blend of adventure, comedy and horror, and could easily have been the foundation of a sustained and commercially successful franchise. Instead The Mummy got killed stone-dead with its second instalment. It was another seven years before Universal returned with a modified cast and a new director to make The Mummy: Tomb of the Dragon Emperor. After that, the studio cut its losses and aimed for a complete reboot. Is The Mummy Returns the worst sequel imaginable? Of course not, but if you asked if it was one of the most disappointing? That leads to a different answer.