A-list superstars in their native electronic-music realm, the robot-masked men of France's Daft Punk have established a foothold among more mainstream listeners thanks to glittery disco-house jams like "Around the World," "One More Time" and "Harder, Better, Faster, Stronger," the last of which traveled farther still after Kanye West sampled it for his 2007 hit "Stronger." So for their highest-profile project to date, you might've expected Thomas Bangalter and Guy-Manuel de Homem-Christo to flex that party-starting flair. No dice. This soundtrack to Walt Disney Pictures' upcoming "Tron" sequel is a determinedly moody affair, longer on minor-key strings and hushed synth burbles than on Daft Punk's revered throbbing beats. That's movie-music business as usual, of course, yet the duo still surprises with the austere beauty of cuts like "Adagio for Tron" and its seamless fusion of organic and electronic elements. The artists' masks are designed precisely to keep us guessing about what's going on in their heads, but who knew it was this?