Directed by Brad Peyton. Starring Dwayne Johnson, Michael Caine, Josh Hutcherson, Vanessa Hudgens, Luis Guzmán, Kristin Davis PG cert, general release, 94 min

HANG ON A moment. To what is this thing a sequel? Oh, yes. If you have children (or were a child in 2008), you may remember an updating of Jules Verne's Journey to Centre of the Earthstarring Brendan Fraser. It wasn't great. It wasn't terrible. Somewhat astonishingly, it made enough money to launch this equally endurable follow-up.

In what many younger folk will regard as an upgrade, Dwayne "The Rock" Johnson replaces Fraser. The scriptwriters' attention moves on to Verne's The Mysterious Island. Luis Guzmán and Vanessa Hudgens offer, respectively, comic cowardice and perky, can-do charm.

The first film supposed that, rather than being works of fiction, Vernes's indestructible books offer guides to fantastic, rarely visited corners of the planet. Part Two goes further. If young Sean Anderson (the always excellent Josh Hutcherson) is to be believed, both Dean Swift and Robert Louis Stevenson were in on the act. Stretching the premise to near breaking point, Sean argues that The Mysterious Island, Treasure Islandand Gulliver's Travelsall describe the same bizarre location in the western Pacific.

Good grief. Such creative inter-textuality is usually the preserve of fat post-modern novels by graduates of Ivy League creative-writing courses.

Anyway, when Sean and his stepdad (Johnson) eventually make it to the island, they encounter tiny elephants, giant lizards and an unnecessarily grumpy Michael Caine (hey, he’s appeared in worse).

It's all a bit silly. But Journey 2does have the uncomplicated charm of those ancient mid-budget epics in which Doug McClure narrowly avoided being eaten by Pterodactyls. Which is to say middle-aged parents may enjoy it more than their less patient digi-children. This writer could certainly tolerate a third episode.