Director Jay Russell (''My Dog Skip'') tells another story of intrepid childhood with his pretty -- and pretty saccharine -- take on Natalie Babbitt's 1975 novel. ''Gilmore Girls'' star Bledel is Winnie Foster, a sheltered rich girl whose attempt to flee her stiff-upper-lipped parents (Victor Garber and Amy Irving) leads her to a woodsy encounter with the Tuck family, who have lapped up immortality from a gurgling spring. She's entranced with the idea, especially as it's embodied in 17-year-old Jesse (Jackson). The lush locations and heavyweight supporting cast (including William Hurt, Sissy Spacek, and Ben Kingsley) almost outweigh the heavy-handed moralizing. Tuck may leave the rainbows-and-unicorns set swooning, but parents will be checking their watches.