’Let s be careful out there, ’ advises Sgt. Esterhaus every morning at roll call. And as the officers and detectives at the Hill Street station house patrol their city’s streets, they must indeed maintain a careful balance between serving their citizens and inciting hostility from criminal elements. Yet as dangerous as their precinct is, the men and women of Hill Street often find that their biggest battles involve protecting themselves from the Public Defender’s office, self-serving bureaucrats and each other.