How do you do the new longer lengths and not look mumsy? That was the puzzle Stella McCartney set out to solve in a collection that played to her strengths. Her answer—box pleats in back, a pair of slits up the front of each leg—was simple enough, but the results were very sexy in her signature breezy way. A silk dress in a vibrant citrus print (first bananas at Prada, now lemons and grapefruit at McCartney) was also slashed at the waist and back, and it had an easy chic that could make it the one thing in your closet you turn to again and again. It just might be the dress of the summer.

In contrast, a denim section of tunics and shorts in boxy shapes looked somewhat clunky. But as ever, McCartney had a lot of strong tailoring, slightly softened this season in a palette of faded pastels like rose, pistachio, and light blue. The other thing that made her suits look new was the cut of the pants. High-waisted, cropped, cuffed, and with a hint of a flare, they stood out in a month full of floor-scraping trousers.

And what of the red-carpet frocks for her front-row gal pals? The designer, who's expecting baby number four, skipped them this season. As an alternative, she showed a pair of double-breasted backless vests, totally on trend and totally McCartney. Salma and Liv would no doubt approve.