Sam and Callen sneak up on a fishing cabin, and they trip a bomb sensor, causing an explosion. Lynn Stiger was killed and stashed in the cabin's closet. Hidoko moved to Los Angeles after her husband was killed. The team checks out a warehouse also owned by Keith Stiger, like the cabin. Traces of ammonium nitrate, which could be used for bombs, was found in the warehouse. Mosley talks to Hetty about their roles. Sam and Callen track surveillance for the warehouse, but the recorders are gone. Stiger's two business partners are worried because they haven't heard from him. The same company that bought a house for Stiger's parents bought an airline ticket for spy Jennifer Kim, so they suspect Stiger is a North Korean spy also. Eric and Nell found the truck carrying the chemicals on surveillance, then Deeks and Kensi went to find it. Jennifer agrees to help in exchange for pizza. Jennifer gets information on Stiger from a former contact. Stiger's plan is unsanctioned. Jen Wu has come to town to help him. Kensi and Deeks find two dead security officers near the empty truck. They, Sam and Callen go into the tunnels in search of the chemicals. They take out a few guards, but Stiger escapes on a motorcycle. The target is LAPD Headquarters. Deeks captures Jen Wu. Sam and Callen catch up to Stiger, but not before he activates the bomb. Callen captures Stiger, who resists and gets killed, then Sam defuses the bomb. Hetty points out that the team worked for Mosley today. Mosley admits she's in LA to re-arrange the NCIS team. Sam and Callen drop by to say thanks to Jennifer. She tells them Granger was her father. She shows them Granger's grave.