The first season finale of NCIS: Los Angeles featured a high-stakes mission to stop an Iranian terrorist's rise to power, a dramatic car chase and some furious gun battles.

That's not what made it memorable, though. The episode title took its name from the label of a binder full of information compiled an some unknown source: "Callen, G."

Information even Callen himself doesn't know.

Executive producer Shane Brennan followed his NCIS finale (follow this link for our NCIS review) by doing much the same here - posing more questions than he answered.

While Callen finally got some answers regarding his past, the season ended on a chilling note, as only in the final moments did he realize he's been followed his entire life.

Has Callen's mother or father been watching him his whole life?

We know that Chris O'Donnell's character has had a troubled past, at least from what little he knows about it. The orphan doesn't even know his own name - just the letter G.

Last night's big plot twist came when the linchpin in the terrorist's plot to recover a vast fortune and launch a rogue government happened to be Callen's sister ... he thought.

The woman was only masquerading as Amy Taylor, nee Callen, having assumed her identity after G's real sister died. But she did know Amy, recalling her vividly to our hero.

We didn't get the first name - so close! Amy only called him "Baby Brother." Still, the scene was particularly poignant and left us more invested in the character than ever.

Also wonderful was the reason Hetty suspended Callen one day. Directing him to the cemetery where Amy rests, he found a note left for her by a parent - his parent as well.

Who knew Hetty's warnings about being careful what you wish for with regard to getting to know your family would ring so true mere minutes later. Is Callen being stalked?

Why would the same person compile a list of the 37 different foster homes he's been in, yet never get to know the boy? How did that information get into the wrong hands?

It was a surprising and compelling cliffhanger, one we have a feeling will further stoke Callen's fire, both personally and professionally, when the show resumes in September.

Initially, it seemed like the abduction, discovery and death of Agent Vaile might have made for a better season finale story arc, and to an extent that still might be the case.

"Callen, G" was an appropriate and dramatic conclusion, however, as the NCIS spinoff fashions itself a character-driven procedural. It had to focus on the central character.

Closing thoughts and observations:

• If we put the over-under for Season One's body count at 500, would you bet the under? These guys (and Kensi) live so dangerously, another casualty can't be far off.
• Linda Hunt really grew on us over the course of the season. Her casting and the entire character of Hetty seemed out of place at first, but no longer. She's the glue.
• Some Sam and Kensi-centric story arcs would be great next year. The first season's solid foundation clearly be improved upon with more character development.
• Ending the season with Callen in the viewfinder of a camera was a cool homage to both NCIS and NCIS: LA's trademark pre- and post-commercial pfoofs/shutters.

What did you think of last night's NCIS: Los Angeles season finale?

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.