A Brilliant Plan - Brilliant - Calendar Moonstone Mysteries, #1

Meet Calendar Moonstone, acclaimed creator of jewelry for the rich, the royals and the famous. And compulsive part-time cat burglar whenever there are rare diamonds whispering her name. It was planned as a routine Thanksgiving part-time job: get in, crack the safe, fetch the diamonds. Instead Calendar finds the dead body of a night watchman and by sheer chance becomes involved to find the murderer and the stolen jewels.
She gets teamed up with a cute police detective and a not so cute insurance investigator who sees Calendar behind almost every jewelry heist ever committed. To stay out of jail, Calendar has to use all her wits, skills and charm. And must solve a century old jewelry mystery.