Though it loses some of its steam before the end, this is an uncommonly affecting and unhackneyed story about a friendship between two alienated 11-year-old boys from neighboring middle-class, single-parent homes, one of whom has AIDS. Working from an original script by Robert Kuhn that mixes comedy and tragedy as if they were kissing cousins, actor Peter Horton makes an impressive directorial debut. Though the story is provisionally about intolerance of and ignorance about AIDS, it focuses on the boys' friendship and adventures--including a Huckleberry Finn-like escape down the river in search of the cure of the title--and the actors do an exceptional job with it, especially Brad Renfro (The Client) and Annabella Sciorra. With Joseph Mazzello, Diana Scarwid, and, in a part that seems to have been severely trimmed, Bruce Davison. Ford City, Norridge, Gardens, Golf Glen, Lincoln Village, Water Tower.