Who says age makes you mellow? A creakier, bitter, more despondent Fleetwood Mac reappear on Say You Will, which reconvenes four-fifths of the lineup that made Fleetwood Mac (1975) and Rumours (1977) before dispersing over the '80s and '90s. Those two albums transformed the band's failing marriages and musical-beds liaisons into such barbed soft-rock anthems as "Landslide" and "Go Your Own Way," wrapping desire and recrimination in gleaming guitars. The group's two '70s stars — sultry-voiced, shawl-twirling sexpot Stevie Nicks and Lindsey Buckingham, who could play anything with a fret board — return and push toward extremes.They tease at continuing the soap opera, directly invoking familiar tunes while exchanging songs about infidelity, porn stars and the reunion of estranged lovers. Buckingham's "Steal Your Heart Away" wishes for a second romantic chance in a folk-rock chorus that the early Byrds would have loved.But their reunion is a quickie: The album ends with Buckingham singing "Say Goodbye" followed by Nicks replying with "Goodbye Baby." It's not the old Mac cooperative; with her latter-day croak, Nicks's harmonies feel like overdubbing, not intimacy. Buckingham, who produced the album, seems more committed to his grimly incoherent political musings and the marvels of his arrangements. "Red Rover" builds a whole orchestra out of picked strings, while "Come" explodes into a garage-rock stomp and guitar flameout. Start the 18-song album in the middle, and embarrassments like Nicks's "Illume (9-11)" (yes, she's burning a candle for the WTC dead) recede behind love songs that exorcise pain with an accusatory chorus and a skein of guitars. That's no longer all they want to do, but they haven't forgotten how.