After two men murder a man in a crowded nightclub, Nate discovers his daughter was an eyewitness. Meanwhile, tensions rise between Sal and Gil on the gang task force, and Sammy confronts his wife, Tammi, after discovering she has been photographing gang members.

Ben learns the hard way, some valuable lessons about the importance of following established procedure and protocol, Lydia's current murder investigation takes an unexpected turn, and Nate and Sammy are unprepared when a group of people they encounter turns into a violent mob.

在胡德日，帮派寻求报复的一天，洛杉矶警察局试图通过在易受暴力影响的社区露营来保持和平。 Sammy和Ben离开他们指定的社区，带来灾难性的后果。与此同时，这个社区抓住了一个千载难逢的机会，寻求对他们一直对他们进行恐吓的帮派手段进行一点点报复。在其他地方，约翰和杰西卡发现另一群邻居会不遗余力地将一名登记的性犯罪者赶出街头。