It's not often that a mediocre young adult sequel's main redeeming quality is its script; words tend to be one of the first casualties of the dollar-eyeballed franchise development process. So Marc Guggenheim's frequently witty, punchy screenplay for Percy Jackson: Sea of Monsters is a pleasant surprise, and becomes even more so when you realise Guggenheim's most notable prior credit is The Green Lantern. But Monsters' story is so weighed down by exposition and laborious mythology that the surprisingly sharp dialogue is lost in the noise.
While nobody at the time would likely have predicted it, 2010's Percy Jackson and the Lightning Thief made more than enough at the box office to guarantee a sequel, and so we're back with mopey demi-god Percy (Logan Lerman). This time out he's grappling with self-doubt over his destiny, residual daddy abandonment issues, and the sudden arrival of Tyson, a Cyclops half-brother he never knew he had (Douglas Smith).
Director Thor Freudenthal (no, really) doesn't stray far from the style established by Christopher Columbus in the first film, balancing banter, exposition and monster-based action efficiently but mechanically. The best material by far is in the first act, with the joyous combination of Anthony Stewart Head – taking over Pierce Brosnan's role as Percy's centaur-mentor Chiron – and Stanley Tucci as Dionysus, the god of wine who's cursed to stay sober.
The supporting cast is strong across the board, with Jackson compensating for the charisma Lerman seems to have misplaced and Rambin bringing spunk and energy to a predictable role. There is a charming, self-aware gem of a movie buried somewhere in here, but the spectacle is so generic and much of the delivery so stilted that it becomes increasingly difficult to find.
The brothers' dynamic is a new wrinkle that adds real value, and Lerman seems livelier in his scenes with Smith than anywhere else, but the third act throws emotional resolution out of the window in favour of shock value and pulled dramatic punches.
There are isolated moments of fun to be had in Sea of Monsters, and standout supporting players make the paint-by-numbers quest story easier to stomach. But it lacks a single memorable set piece or story point, and you'll be hard pushed to find a flatter pair of lead performances than Lerman's and Daddario's.