Sep 30, 2014 Updated: 2:27 PM
A modern, edgy drama full to the brim with passion, politics and peril. MI-5 leads us into the dangerous world of Britain's top-secret security agency, and into the lives of people who must lie, and sometimes die, for a living.
VISIT THE BBC's MI-5 WEB SITE
Martin's estranged parents visit; school secretary Maureen Tracey visits the doctor for a thyroid problem; Danny Steel collapses and needs emergency surgery to save his life.
Find out about upcoming shows, special events, and discounts.