Tina Lutz and Marcia Patmos set their collection at the seaside at the start of summer. As they designed, they were imagining the opening of a beach house after a long, gray winter—letting in the light, taking that first walk on the dunes. This poetic vision was applied to the clothes with appropriate abstraction: Dresses were adorned with wavelike ruffles, a tactile gold-leafed cardigan featured a shell stitch, and a chartreuse sweater had snail-like braid embellishments.

"Seasonless" is a term that could be applied to both the clothes and to the house's celebrity guest designer of the moment: Jane Birkin, the actress and activist—and Lutz's idol since the age of 10—who contributed an off-the-shoulder V-neck and tank. (Past collaborators include Kirsten Dunst, Carine Roitfeld, and Richard Meier.) Airy knit laces, like most of the sweaters, were light enough to wear on a June evening with a chill in the air.

Lutz & Patmos, of course, made its name with cashmere—a winter thing, it used to go without saying. But, eco-conscious and aware of the quickly changing climate, they are of the opinion that all designers, of knitwear or otherwise, will have to start thinking beyond seasons.