Season seven of British spy thriller quot MI-五 quot opens with Adam Carter Rupert Penry-Jones valiantly battling to move a car bomb away from a densely packed memorial service Meanwhile Harry secures the release of Lucas North Richard Armitage , a MI-五 officer imprisoned in Russia for eight years Its not long, however, before Ros begins to suspect Lucas loyalties The rest of the season deals with a top secret Cold War-era operation named Sugarhorse