A group of MI5 agents are banished to a backwater office for various failings. Their irascible boss, played to perfection by Gary Oldman, doesn’t seem like much, but he’s a canny old spy who’s better than he seems. When a young man is kidnapped by a group of ultra-nationalists, the group (the slow horses) are plunged into intrigue and danger as they race to save him while covering their own backsides.