The stakes are raised in season two of "MI-5", as the threat to national security increases and the need to thw the terrorists operating within the UK bees more urgent. Tom is investigating a Serbian terrorist plot. His girlfriend and her daughter are trapped in Tom's house with a lap- which is thought to ntain a bomb. Meanwhile another bomb is primed to explode and this one kills the Secretary of State for Northern Ireland. Adding to the possible dangers faced by other government officials, Tom learns from his American lleague that an assassin is in town, the CIA know about him but they haven't told MI-5.