The Rhythm Section — Mark Burnell

Her life was destroyed when the plane carrying her family crashed. Now Stephanie will do anything for revenge....Recruited by a covert intelligence organization, she makes a deal. Complete their lethal assignments and they'll let her kill the murderers who destroyed her family. Young, smart, and beautiful, she becomes an assassin with two covers--"Petra," a terrorist-for-hire in Germany, and "Marina," an international businesswoman in London.

Immersed in the brutal, high-stakes world of international terrorism, Stephanie begins to ask some deadly questions. Is the organization telling her the truth, or are they using her for a darker reason? Is avenging her family worth losing her soul? And will the organization that created her let her go--or is she already the next target? She's got one chance to escape--if she lives long enough to take it.

"Drums and bass are the rhythm section. Your heart is the drums, your breathing is the bass. You get those two sorted, then you're sorted. You can't panic when your breathing's under control and you've got your pulse in check. It's not physically possible."