Danny and Baez investigated a decapitated dead body that washed up on shore. It has a tattoo associated with the Mexican Mafia. His name was Manny and he was a drug runner but his girlfriend said he tried to get out of the life and ended up dead.
Baez hears from an old boyfriend in the DEA that Luis Delgado (aka The Panther) is the person who killed Manny and is also believed to have set Danny’s house on fire.
Danny is furious when Erin says he doesn’t have enough for a warrant to arrest Luis or search his residence. Danny and Baez break into his home anyway and when he fights back, they arrest him. Luis taunts Danny once they’re alone, admitting to the fire. Erin says she can’t arrest Luis. He has no criminal record and there is no evidence and only Danny’s word. Once again, Danny is furious.
Luis murders Manny’s girlfriend and calls Danny to taunt him. Erin does get a warrant to pull Luis’ cell phone records and they are able to figure out when the next shipment of drugs comes in. Luis taunts Danny once again, making it sound as though he had something to do with Linda’s helicopter crash. Danny and Baez arrest six people but let Luis go, making it look as though he was working with the police. Later, Luis turns up decapitated on the shore.
Erin gets promoted to Bureau Chief and brings Anthony along as her lead investigator. She’ll now be supervising 50 attorneys but her boss makes it clear that she needs to keep a healthy balance between her job and her family.
Frank considers having Sid draw up an Interim Order to prevent partners who are engaged from working together but Abigail talks him out of it, saying he’d be doing it just to target Jamie and Eddie.
Jamie and Eddie stumble upon an apartment building fire and both run in to save residents inside before the fire department arrives. One man ends up dead. They arrest Justin Matthews who says someone told him to do it and that no one was supposed to be inside but he won’t give up a name and is arrested for second-degree murder.
Jamie insists on continuing the investigation. Turns out the landlord of the building is Justin’s father. He was trying to drive out the last tenants so he could sell the building. He turns himself in to save his son.
After a tension-filled Sunday family dinner, Eddie thinks she and Jamie should reconsider continuing to be partners. Jamie doesn’t want to cow-tow to his family but Eddie says all she wants is him. Henry later points out to Frank that his first reaction wasn’t to be happy about the engagement but to point out the problems with being partners. Erin tells Jamie that their father isn’t being combative but is fearful for Jamie and Eddie’s safety.
Turns out Jamie did take the Sergeant’s exam and had the top scores. Eddie also took it and did well. Jamie tells Frank he’s decided to take the promotion and the two toast to that and to his engagement.