Street is caught between his duty to SWAT and his commitment to his foster brother, Nate when Nate is ensnared in a criminal enterprise that could ruin them both. Also, the SWAT team goes after a ruthless crew that uses deadly force while stealing from card casinos, and Buck approaches Deacon to partner on a private security opportunity.

Tan is left reeling when his girlfriend is kidnapped, and 20-Squad must race to track down a violent cartel leader who may be behind the abduction.

When three of L.A.'s finest are targeted and gunned down in the street, the team enlist the help of an LAPD psychologist to stop a murderous rampage, reopening old wounds tied to the department's failed response to a school shooting.