Based on Roslund & Hellström's novel Three Seconds, The Informer is the story of an ex-convict Pete Koslow (Joel Kinnaman) turned undercover mole. He is expected to visit the place he dreads the most - Bale Hill Prison. A drug deal-gone-wrong threatens to expose Koslow as a mole. Not only that, his family's life is also at stake. Will Koslow be able to escape prison and protect his family all the same?