There was a roomful of happy faces at L'Wren Scott's Gagosian Gallery show. Not an easy feat for the last day of fashion week. And it was more than just the bento boxes and sake—or the sighting of Scott's beau, Mick Jagger—that had people smiling. This longtime stylist-turned-designer's clothes are steamy, sharply tailored, and, even better, trend-free.

She opened with a trio of long sweeping coats, worn with matchstick-skinny jeans and trilbies angled just so. From there, she dabbled in daywear, showing fitted blazers, cropped to graze the hips, and a pair of body-loving dresses—one with bracelet sleeves, the other boatnecked and sleeveless. Scott, of course, has made her reputation dressing celebrities for the red carpet, so eveningwear of a get-me-noticed sort was the bigger focus. Working in black, many shades of blue, and nothing else, she scored with a whippet-thin suit in allover sequins, a stretch-satin cocktail dress topped by a directional cape, and an hourglass gown that had a sweetheart neckline edged in netting and a cascade of tiered ruffles at the back.

Now in her fourth season and feeling confident, the designer mixed it up. A short lace dress and a sleek zip-front jumpsuit added a sexy, and refreshingly personal, rock 'n' roll edge. Credit Scott for ending fashion week on a positive note.