"Fifth Mission" follows a methodical hitman who believes he is cleaning society by killing those he deems beyond justice. When a detective begins tracking the killer after his brother is killed by him, the pursuit becomes deeply intimate, blurring the line between law, revenge, and moral authority. As both men move closer to one another through the streets of Viborg, their shared conviction that they are doing what must be done raises a dangerous question, how far can justice bend before it's justice no more?