Brief episode synopsis:

• Sam is sent undercover as a bomb specialist as the team races to locate stolen explosives somewhere in the city.
• Hunter changes the dynamics of the team and has Callen partnered with Kensi and Sam (amusingly) with Deeks.
• The team is unable to defuse the bombs in time but escapes unharmed, with the perpetrator stuck inside.
• Hunter had been working this case undercover for some time, and leaves to continue its next phase.
• Hetty returns and shares some of the details of Callen's past with him at last.