To celebrate the new release of Andy McNab's Dead Centre, we are giving away a set of the last four titles in the Nick Stone series for the ultimate catch up. Join the ex-SAS mercenary in Brute Force, Exit Wound, Zero Hour and the newest episode Dead Centre. Stone is hurtled into his most complex and compelling mission yet, following the kidnap of an oligarch’s young son and heir, but what has led Nick Stone to his latest operation? This is your chance to find out.

For the opportunity to be the lucky winner of this thrilling series, brought to life through Rupert Degas' gripping narration, answer the question below.