A woman gets attacked by a masked man, then run over by a train. A special mayoral election is being held during Mardi Gras. The woman was Chief Erica Cross, who was working with Muslim refugees. Percy is taking personal time. When LaSalle and Gregorio confront the woman Erica last called, Noora Saadi, her son Sharif runs, and LaSalle finds a jihadi flag and bomb-making instructions. Noora said Erica called because she was concerned Sharif was being recruited as a terrorist. Pride has Loretta talk to Noora. On video at a hookah bar, Erica is seen eavesdropping on Sharif's conversation with a man, and he stopped the man from going after Erica. Noora reunites with Sharif, then he gets abducted by masked men in a van. Noora said Sharif is being forced to kill the mayor. Pride warns Mayor Taylor that she is the target of a terrorist attack. She refuses to stop campaigning. So Pride protects her, while LaSalle and Gregorio search for Sharif and the terrorists. Sebastian figures out the terrorists are using a fertilizer bomb. LaSalle and Gregorio fail to catch Sharif, who is driving a boat full of explosives. Pride and police shoot and blow up the boat. It wasn't Sharif driving the boat, but a drugged man, with the boat driven remotely. Zahra goes to stand with the refugees, rather than lay low. Patten pinpoints the terrorists' location, and the team takes them down, rescuing Sharif. The terrorists are actually mercenaries. Noora has on an explosive vest at the refugee center. Pride calls Loretta's phone so Sharif can talk with his mother, and she surrenders. Media mogul Ron Cook was behind the fake terrorists, so the team arrests him. Mayor Taylor wins the election. Pride and company celebrate with a king cake baked by Noora.