Susan (Melissa McCarthy) is a CIA logistics staff member who specializes in assisting in dangerous missions but is unknown to the public. Her partner Bradley (Jude Law) suddenly disappeared during an operation, which also affected the safety of another top CIA agent Rick (Jason Statham). In order to find out the whereabouts of her partner and save this precarious world, Susan volunteered to act as an undercover agent and infiltrated the most dangerous arms dealer group in history, trying to find out the truth of the matter and fighting wits and courage with the femme fatale leader (Rose Byrne). However, in the thrilling process of heroic rescue, Susan found that things were far from as simple as she imagined...