Mission: Improper

Sienna Frances’ narration is the secret weapon of this audiobook—she’s the kind of performer who makes you forget you’re listening to a recording. Her voice drips with the effortless charm of a rake who knows exactly how dangerous he is, and she nails the tonal whiplash of shifting from sultry flirtation to lethal intent without missing a beat. Caleb Byrne’s sarcasm sounds like it’s being delivered directly into your ear by a man who’s equal parts exhausted and entertained by his own chaos, while the supporting cast—from the ice-queen strategist to the perpetually scheming chemist—each get distinct, memorable voices that never feel forced. The pacing is relentless, with McMaster’s sharp chapter breaks keeping the momentum from flagging, even if the final act’s frenetic twists occasionally left me scrambling to keep up. That said, the romance subplot feels a tad too neatly resolved, and the villain’s monologues occasionally teeter into caricature territory—more mordant than menacing. Still, Frances’ performance elevates the material so effectively that even the clunkiest dialogue lands with a thudding impact. By the time Caleb delivers his final speech, you’ll be clamoring for the next installment, preferably narrated by Frances and with a shot of absinthe in hand.