Writer-director Paul Andrew Williams’s Unfinished Song is a full-frontal attack on its audience’s tear ducts. Shamelessly manipulative, it’s a highly effective if not very good film, its success entirely due to the talents of its cast. They bring heart to a script that is unabashedly about pushing buttons. Vanessa Redgrave plays Marion, an elderly woman fighting cancer as her gruff husband, Arthur (Terence Stamp), and adoring son, James (Christopher Eccleston), struggle to come to terms with her impending death. Father and son have an icy relationship that pains her. But all is not gloom. Marion sings in a multiculti choir of senior citizens rendered cutesy in that time-honored silver-screen way; they’re both harmlessly raunchy and puppy-dog lovable. Their earnest, unlucky-in-love young choir director, Elizabeth (Gemma Arterton), leads them through peppy arrangements of heavy metal and rap songs that the elders perform with adorableness to spare. (Marion’s crooning of Cyndi Lauper’s “True Colors” to Arthur, however, stops just short of flashing a “Cry, damn it!” card at the audience.) The film is ultimately about the redemption of Arthur, him finding his heart and reconnecting with his son before it’s too late. Williams uses a sledgehammer to drive that message home, but the velvet touch of his cast (particularly Redgrave) almost salvages this.