Pantro Torres, the leader of a powerful New York street gang El Puno, is found murdered; impaled and pushed from the balcony of his hotel room. Mac and the team must find the killer before the gang takes revenge and starts a bloody street war with their rivals the Mambas street gang. DNA at the crime scene leads them to a former rival gang member turned high-end escort, Hazel Ortega. Det. Flack tracks Hazel down and as he is driving her to the precinct they are ambushed by a pair of gunman. Hazel survives and tells Jo she was in the hotel room the night of Panthro's murder and saw someone else enter as she was leaving but is too scared to give Jo a name. The co-founder of El Puno, Luther Devarro, was just released from prison after Mac put him away 15 years ago. Mac goes to Luther for info and cooperation. Luther, trying to gain Mac's trust, tells him where to find the shooters that ambushed Det. Flack and Hazel. The team knows that the heads of El Puno are being targeted and decides to bring all remaining lieutenants in for questioning. In the process, the gang's main head quarters explodes killing the brains of the gang's business operations. Sid finds that she was shot and killed before the blast ever took place. A palm print at the scene of the explosion reveals that Luther is the killer. Mac finds Luther about to kill the last lieutenant, his brother Rick. Rick doesn't believe Mac's accusations of Luther guilt and gives chase; shooting Mac in the process. Mac is forced to shoot Luther but realizes Luther shot Rick to save Mac's life. Luther was ashamed that the gang he started to protect his neighborhood was now destroying it and followed the rules of the street to the end; even if it meant his own life.