AC-12 is a fictional police unit featured in the British television series Line of Duty. The unit specializes in investigating police corruption and misconduct within law enforcement agencies. Its members are dedicated to uncovering the truth and ensuring accountability among officers. The team is led by Superintendent Ted Hastings, along with key characters DI Kate Fleming and DS Steve Arnott. Throughout the series, AC-12 faces various challenges, including internal politics and complex cases, while striving to maintain integrity in their investigations.