Starring Hilary Duff, Jason Ritter. Written by Sam Schreiber. Directed by Sean McNamara. (PG) 106 min. Opens Oct 8.

Hilary Duff is a monster. Over the course of Raise Your Voice’s hideously overextended 106 minutes, Duff spends half the time lying to her father; she turns her boyfriend into an underage alcoholic; she gets her brother killed in a car crash; and she sings at least four songs. A Cinderella Story, the tween idol’s last project — the word "movie" seems somehow pretentious — at least had the taste to just include Duff’s music on the backing soundtrack. Raise Your Voice, however, set at a Los Angeles music summer school, is never so delicate. Viscous, sub-Shania Twain pop coagulates through every painful minute, from beginning to freeze-frame end, each melisma and cadenza the aural equivalent of that hammer blow to Jimmy Caan’s ankles in Misery.

In other words, what’s not to love? Raise Your Voice is as good as bad gets. H-Duff plays Terri Fletcher, an upright, uptight Christian girl from Arizona, who’s accepted into the summer program at the Bristol-Hillman Music Conservatory — "the greatest music school in America!" The trouble is, her mean ol’ pa (Simon Fletcher), still understandably wracked by the death of his son (Jason Ritter) in a mysterious truck-squishing incident, won’t let her out of his sight.

But the show must, alas, go on, and H-D’oh manages to escape to LA thanks to the scheming of her artsy aunt Nina (Rebecca De Mornay). The overlong second act sets up the Bristol-Hillman setting, with Duff harangued by the obligatory school queen-bitch Robin (Lauren C. Mayhew), and ickily wooed by Jay, a smarmy Brit-kid (played by Oliver James, who despite hailing from the UK, somehow has a less convincing English accent than Buffy’s Californian James Marsters). Needless to say, it all ends happily, with a show, some songs and lotsa tears — but at nearly two hours, even Duff’s fans will be checking their watches.