Abandon hope all ye who enter Stephen Gaghan's directorial debut expecting it to build on the promise of his Oscar-winning ''Traffic'' screenplay. As a long-lost ''Dawson's Creek''/''Law & Order'' crossover, however, it ain't bad. Once again, as on ''Dawson's Creek,'' Katie Holmes plays a head-of-the-class undergrad who's oblivious to her knee-weakening effect on men; and as he once did on ''Law & Order,'' Benjamin Bratt plays a brooding detective -- only in this case, he's investigating the disappearance of Holmes' rich-brat boyfriend (''Undeclared'' alum Charlie Hunnam).

Sometimes, typecasting works: Holmes and Bratt settle comfortably into their roles, and the movie proves a competently made, mildly diverting collegiate thriller -- at least until its all-too-predictable ''twist'' ending. Among an overachieving supporting cast, Zooey Deschanel (''The Good Girl'') and Melanie Lynskey (''Heavenly Creatures'') score the highest marks as two of Holmes' loopier classmates.