Dec 19, 2013 Updated: 1:44 AM
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
Ruth finds herself on the wrong end of an investigation after witnessing a man commit suicide; Harry directs the team to investigate a fire at Cotterdam Prison that killed seven terror suspects.
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