In this episode, the police investigate a quinceañera massacre; one of them may pay the ultimate price, and a district attorney is set to take the law back into his own hands.

When a normal quinceañera erupts in violence when several men masked in bandanas open fire on the party leaving multiple people dead, Detectives Winters and Jaruszalski quickly follow leads.

During their search for answers, they find an eleven-year-old Yaqui Indian boy from Sonora, Mexico named Fernando (Quinton Lopez) protecting acres of marijuana in Zuma Canyon, and discover he is the only witness that can help the case, although he does not talk and tell them who he is because he fears the man with "snakes feet" – Caesar Vargas (Jose Pablo Cantillo), who owned the marijuana field.

Morales wonders how it will look for the DA's office if he quits and returns to the police force, because his boss is too vain to ask for help in bringing a cop killer to justice.

[3] In its original American broadcast on April 11, 2011; "Zuma Canyon" was approximately viewed by an estimated 6.10 million households with a 1.5 rating/4% share in the 18–49 demographic in the two-hour range of episodes.