"I'm moving on from pretty and becoming stronger and sexier!" Alice Temperley announced mid-gush about the outrageous glamour of her new muse, the seductress-spy Mata Hari.

It was quite a declaration from a designer who has built her house on a lace-and-bugle-bead foundation of flirty tea frocks and party confections. But she kept her word—mostly—on the runway. Here, for a change, was black leather, cut into a provocative pencil skirt and hot-to-trot thigh-high boots; here were sharp, smart soldier jackets. Even the evening gowns had taken on a decidedly harder edge (although, it must be said, a metallic green number was too tooth-grindingly aggressive). The designer did take care of her international coterie of Temperlettes, however, cleverly doling out, between the darker fare, the needed pretty fix: intarsia sweater dresses, sunbursts, and a breezy, ruffled cream dress that only required a change of shoes to be all sweetness and light.