What a difference five months makes. Since Adam Selman debuted his line last September, he has been picked up by a bevy of key retailers, including Opening Ceremony and Browns of London, and is working with one of the biz's most prestigious PR firms. Does the fact that he's Rihanna's costume designer and the cocreator of her recently wrapped River Island capsule have anything to do with that? Maybe. But we've got to give him props. Last season, Selman seemed like Riri's costumer who just happened to have a clothing line. This time around, he came off as a designer with a vision who just happens to collaborate with Rihanna.

Selman's Fall story grew out of a bizarre current event: About four months ago, a hiker in the French Alps stumbled upon $300,000 worth of jewels. Allegedly, they were relics from a plane that crashed there in the 1950s while flying from Bombay to New York. "So it's hiking clothes meets India, but in a weird, New York, Stephen Sprouse kind of way," said Selman. How did he pull that off, exactly? For starters, there were his prints—a paint-splatter-cum-cow-spot pattern, and a seed motif that referenced traditional saris but was rendered in such a way that it recalled an urban grate.

The designer's campy-flirty take on sportswear did the rest. Jersey caftans, a tech-fabric pencil skirt, luxe sweats galore, and playful wide-leg overalls, all worn with red or cobalt heels, blended far-flung glamour, athletics, and city life. There were easy, pared-down options too, like high-waisted twill trousers and a nubby wool bomber, as well as clever touches of sexed-up glam. For instance, one look—a black body-con floor-length dress and matching opera gloves—was made entirely of sport mesh. A hooded black jumpsuit paired with a snood seemed equally saucy (not to mention comfortable). Same goes for a roomy blue sweat suit, if only because it was shown with a hip-baring leotard (presumably this ensemble is Rihanna-approved).

The details here—namely grosgrain embellishments, unexpected mesh panels, and braided backpack straps—deserve a nod. As do Selman's ribbed hats, the tops of which were knotted into floppy little bows. Apparently, they were born during a hazy night at home. "I was just playing around with some fabric and tied it around my head, and that was it. But it kind of came out TLC," he said backstage. No need to overthink it, Mr. Selman. Whatever you're doing, it's working.