Box Office Preview: Can 'Mortal Instruments' Break the 'Twilight' Curse?

The $60 million adaptation of Cassandra Clare's best-selling book series was produced and financed by Germany's Constantin Films.

A condensed version of this story will appear in the Sept. 6 issue of The Hollywood Reporter magazine.

The Mortal Instruments: City of Bones hopes to be the next young-adult film adaptation to win over the hearts and wallets of teen moviegoers, but it faces significant challenges as it opens in U.S. theaters on Wednesday, Aug. 21.

PHOTOS: Teenage Dreams: 17 of the Most Popular YA Properties Adapted for TV and Film

Tracking suggests the movie will post a subdued five-day opening in the $15 million range. Starring Lily Collins as a girl who discovers she's part of a secret order of half-angel warriors, City of Bones will have to battle Edgar Wright's dark comedy The World's End, headlined by Simon Pegg, and horror pic You're Next -- though those two films don't open until Friday.

City of Bones is a major gamble for Germany's Constantin Films, which financed and produced the $60 million movie. Sony's Screen Gems acquired U.S. rights to the title, the first in a planned franchise. If it does prove soft in the U.S., Constantin is hoping to make up the difference overseas.

Bearing obvious parallels to the hit vampire series Twilight, City of Bones seems ripe to fill the void left by the end of that franchise. But with the exception of Hunger Games, YA-novel-based movies have generated mixed results.

Warner Bros.' Beautiful Creatures had all the makings of a Twilight-like hit: based on a hot YA four-book series (that has sold more than 1.3 million copies in the U.S.); young, attractive leads; and a passionate, youthful love story. But it opened in February in sixth place with $8.9 million at the domestic box office, behind Warm Bodies, which was in its third week of release. Insiders say one of the main reasons that the big-screen adaptation failed was that it was significantly different from the book, which alienated the series' extremely rabid fanbase. Some fan sites even told people to boycott the film.

FILM REVIEW: The Mortal Instruments: City of Bones

Mortal Instruments producer Robert Kulzer of Constantin Films says he was very aware of the backlash surrounding Beautiful Creatures. "It's a bit of a mystery. On paper, I'm sure they had it all figured it out," he says.

Kulzer says that City of Bones, at 2 hours and 10 minutes, is longer than the studio would have liked, but that he and director Harald Zwart were not going to make a film that wasn't loyal to Cassandra Clare's book series, which has sold more than 24 million copies worldwide.

"We had to break a lot of rules," he says. "If we'd tried to squeeze this book into the current movie formula, we would have had to change so much that we would've ended up with something that the fans don't like."

STORY: 'Mortal Instruments: City of Bones' Premiere Brings the Next YA Adaptation to Life

A second attempt to emulate the success of Twilight came in March with the release of author Stephenie Meyer's next book, The Host. While the film, starring Saoirse Ronan and directed by Andrew Niccol was not expected to match Twilight's numbers, the sci-fi pic became a disappointment when it landed in sixth place its opening weekend, grossing only $10.6 million -- less than one-third of the first-day gross of the first Twilight film in 2008 ($35.98 million). The film was about aliens instead of vampires, but it still featured a cast of young, promising actors and had Meyer's name on it.

Is oversaturation a problem? "I think so," says Kulzer. "We like the idea that we're a little bit of an underdog. If you have a couple million books out there, that [doesn't mean] you instantly have a theatrical success." With more than 50 YA properties currently in development for movies, Hollywood is watching to see if the latest effort suffers the "Twilight curse."

Pamela McClintock contributed to this report.

E-mail: Rebecca.Ford@THR.com

Twitter: @Beccamford