The team searches for a suspect and their motive following the bombing of a large facility where military combat drones are assembled. Meanwhile, Callen and Killbride get troubling news about Hetty when a body matching her description is found in Syria.
After an architect duo who specialize in designing secure buildings is kidnapped, the team mounts a search to bring them home. Meanwhile, Deeks and Kensi realize they may need to get Rosa some help with her schoolwork.
The team joins forces with the FBI when a group of grisly murderers known as "The Body Stitchers" returns after evading capture by NCIS years ago. Meanwhile, Sam's dad makes a new friend in Arkady. Note: This episode follows on from "The Monster" NCIS: Los Angeles season 9 episode 17
When Aiden Hanna's plane crashes and he is accused of being at fault for the accident, the NCIS team must investigate to clear his name. Meanwhile, Rountree considers how he wants to handle the aftermath of the incident with the LAPD.
NCIS is called to investigate when a woman is seen fleeing the scene of her husband's murder. Meanwhile Roberta Deeks comes into town to meet Rosa and Sam looks for another aide for his father.
NCIS is called to investigate after Rear Admiral Ted Gordon is abducted from his home. Meanwhile, with Deeks off apartment hunting with his mother, Kensi struggles with being the fun parent.
A Marine falls ill during a training mission due to an attack by a genetic weapon, sending the team on a race to find and stop who's responsible. Meanwhile, Deeks struggles with balancing work and home life when Rosa comes down with the flu.
NCIS investigates an arson attack at Global West Ventures Corp., a naval defense contractor. Meanwhile, Rountree connects with an ex and Kilbride gives Callen files on Pembrook.
When NCIS investigates a shootout on a boat in which a rare cultural artifact is stolen, they're shocked to learn who owns the boat.
As Kilbride goes missing, Fatima and Roundtree are attacked by gunmen led by rogue CIA agent Morgan Miller with the abduction seeing Roundtree being kidnapped. The team continues to work with their D.C. and Hawaii colleagues to find Roundtree, who is tortured for information on Kilbride's whereabouts while the teams learn their identities have been posted on the Dark Web which means every cartel member, hitman, gang and psychopath are also after them to claim the bounties on their heads. ----
When Sam's friend Tom Olsen finds himself being hunted down by enemies from his past, the NCIS team must find out who is after him.
While investigating a missing Navy Lieutenant with ties to a dangerous Islamic militia, Kensi and Fatima are abducted and drugged, waking up inside a car that's due to explode any moment, sending the team into a desperate race against time to find and save them before it's too late.
When the founder of an AI company is attacked by a mystery woman, the team must identify her before the next major global conflict erupts. Meanwhile, Kilbride receives a visit from his ex-wife who wants him to reconnect with their estranged son.
When a Petty Officer serving on the U.S.S. Allegiance is found with an apparent suicide note, the team is tasked with investigating. Meanwhile, Callen and Anna begin the process of planning their wedding and Sam has a conversation with his daughter, Kam.
When LAPD Detective Ellen Whiting shows up at Kensi and Deeks's house, asking for help in regard to a fellow LAPD Detective who's been murdered, the team investigates a group of potentially corrupt LAPD cops who are connected to a gang dealing drugs on the streets of Los Angeles. Sam goes undercover as a fighter to find out more information.
When the team receives an urgent, cryptic message, they discover it's connected to the Drona Project and Pembroke, sending the team on a race to solve the case. Meanwhile, Kilbride plans to finally visit his son who he hasn't seen for ten years, and Callen asks Sam to be the best man at his upcoming wedding.
As Kilbride reconnects with his estranged son Alex, the team assists NCIS's cold case homicide unit on an investigation concerning the disappearance of a Navy Petty Officer in 2003, the case soon turning into a murder investigation.
The team investigates when a Navy reservist is stabbed and his lab full of pesticides and insects is ransacked. Meanwhile, Kilbride makes Sam an offer and Roundtree begins thinking about his future.
The team investigates when four people including an officer with the CIA are shot dead in broad daylight with the investigation leading them towards the Drona Project. Callen meets Pembrook who offers insight into Callen's own past. The two later battle to survive against the remaining survivors of the Drona project who seek to kill Pembrook by any means necessary.
The team helps the ATF SAC Kerry Adams with an investigation into illegal weapons smuggling, while also investigating if an active undercover ATF agent is a traitor. The episode ends in a cliffhanger with Callen and Sam pinned down by Adams, who is the real traitor. Meanwhile, Rountree's sister Jordyn interviews for candidacy to medical school, Sam tries to persuade his father Raymond to join a drug trial, and Arkady attempts to aid with Callen and Anna's wedding preparations, much to their irri
After surviving the gunfight, Callen and Sam regroup and continue helping their colleagues search for the missing military-grade weapons. After the case has been solved, Callen and Anna decide on an impromptu wedding, attended by friends and family at City Hall. While getting ready, Kensi and Deeks are stunned when they learn they are expecting a baby. During the reception, Callen receives a letter of congratulations from Hetty, who also asks him and Sam to join her for a "side project" in Moroc