Mel's past military expertise proves critical when McCall is hired by District Attorney Grafton to find a sniper on a killing spree, seemingly selecting victims at random. Also, Delilah experiences PTSD when the sniper shootings cause her to relive the trauma of her friend's fatal shooting.

McCall and Mel help a deported woman track down her son after she was separated from him while seeking asylum at the U.S. border. Also, Mel, McCall and Bishop exhaust every avenue to get Harry released from prison