The story follows , a professional mercenary who travels to Brooklyn to attend the funeral of his brother, Randall, a high school teacher murdered during an attempted carjacking. Suspecting the death wasn't a random crime, Karl goes undercover as a substitute teacher at his brother's former school to investigate.

: A veteran actor known for Hair and Everwood , Williams took over the franchise lead and would go on to star in two more sequels.

Once inside, he discovers a ruthless gang known as "The Brotherhood" is running a massive stolen-car ring right out of the school's auto shop. To dismantle the operation and find his brother's killer, Karl uses his lethal military training to take down both the gang members and the corrupt staff members protecting them.

: The school's auto-repair teacher and one of the primary antagonists.