Danny and Linda end up in the middle of a bank robbery where Danny quickly deduces that the robbers are ex-military. With the help from the DNA off of a cigarette butt left behind, Danny tracks down the robbers but doesn't have enough proof to arrest them.
He later figures out that they robbed the back to get money to pay for Capt. Richard Sullivan's medical treatment. He lost both his legs and suffered a traumatic brain injury while in combat but the VA hasn't approved his treatment. His wife, Angela was one of the bank robbers.
Danny gets incriminating photos on Angela of her kissing another man and uses them to flip her. The robbers each get five years in prison and Danny uses one of Erin's contacts to help get Sullivan's treatment approved so he can be admitted to the VA hospital.
Jamie and Eddie come across an abandoned duffel bag and call in the bomb squad. It turns out to be a blow up piece of art, set up to look like a bomb. It was done by a street artist only known as Spanky.
Garrett wants to write off the event as a prank while Gormley sees it as terrorism. The two argue vehemently. Frank wants the artist found and charged with a felony hazardous act. Garrett feels threatened by Gormley, even more so when he thinks he's been left out of a meeting, even though Frank makes it clear that that isn't the case.
Later Garrett realizes that Gormley had a point when Spanky is finally found.