Ordinary Brooklyn teen Lily Collins turns into a kick-ass demon-slayer after learning that she belongs to a long line of half-angel warriors.

This romantic fantasy-adventure could easily be dismissed as a Twilight rip-off, yet director Harold Zwart and his stars give this adaptation of Cassandra Clare’s bestselling novel a playful zip.

Collins is appealingly sassy and is well partnered by swaggering Jamie Campbell Bower as a fellow Shadowhunter and Robert Sheehan as her geeky best friend.

Admittedly, the plot is absurdly convoluted and derivative, but that doesn’t mean you won’t have fun encountering a world where warlocks and werewolves lurk behind normal guises and a slobbering dog suddenly transforms into a slimy, tentacle-waving monster.