Despite having solid field training, CIA analyst Susan Cooper (Melissa McCarthy) has spent her entire career as a desk jockey, working hand-in-hand with dashing agent Bradley Fine (Jude Law). Using high-tech equipment and a hidden earpiece, Susan is the guardian angel who helps Bradley avoid danger. However, when Bradley is assassinated by Bulgarian arms dealer Rayna Boyanov (Rose Byrne), Susan wrangles her way into her first undercover assignment to help capture Boyanov and avenge Bradley.