A man kills his dining partner with a hypodermic needle. The Treasury Department has been hacked. The stabbed man, Logan Gorman, is one suspect in the hack. Deeks' old friend, NSA Agent Michael Donaldson, is investigating the hack. Tara and Paul Nelson are the other suspects. Hetty has a special assignment for Callen, so Sam pairs up with Anna to investigate Gorman's murder. Hetty brings in Digital Forensics Specialist Dave Flynn to cover in Ops for Nell and Eric, who are going undercover at a couples' retreat in search of the Nelsons. Deeks and Kensi are tailing them in an RV. Nell and Eric meet the Nelsons and pair up for the couples' exercises. Searching Gorman's house, Anna and Sam determine he was involved with the Nelsons. Callen discovers Joelle at the home he's been staking out. Callen approaches her, and she agrees to meet him later. The Nelsons are acting skittish around Nell and Eric. Flynn figures out Trevor Young killed Gorman, and is after the Nelsons next. Anna and Sam find Trevor dead and Sam kills an Arab shooter. Nell and Eric lose the Nelsons during a scavenger hunt. Joelle explains that she was with her actual family. She says that no one has heard from Sabatino. The Nelsons said that they're passing off the data because Tara's sister has been kidnapped, and that a man had beaten up Paul and taken the flash drive. Sam and Anna go to the headquarters of the Arab's brotherhood and rescue Tara's sister. Kensi and Deeks chase the man with the drive in their RV. but can't catch up. Eric and Nell end up shooting up the Arab's truck. Then Nell gives Eric a kiss, which Deeks shoots a photo of. Hetty admits she sent Callen to Joelle's house to give him perspective.