Working with Gibbs (a NCIS story)

Chapter 22: I'm sorry...what?

-about a week later-
Ziva left to find Ari, and things were normal for...about...a week - new record, actually - but that doesn't last long...
It was mainly cold cases that the team was working on, an occasional open and shut case, but nothing major.  One night, the rest of the team left while Grace and Gibbs stayed behind to finish up some things.  After a while, Grace stood to leave.
"As much as I'd love to continue to stay here, my eyes can't take any more case reports...see you at home later?" A nod was all she got, but that was to be expected when he was in work mode.  She waved bye and left - thankfully she still was bringing her car in to work.
-about 10 minutes later-
She went into the house and turned on the lights, surprised to see someone else there. 
"NCIS!" She yelled.
"FBI!" the man called at the same time.  She took a deep breath and started over.
"Who are you?"
"FBI agent Fornell.  Who are you?"
"NCIS agent Grace Williams.  Why are you here in my house?"
"What are you talking about? This is agent Gibbs' house..."
"Yeah, I know that...again, why are you in my house?" He was shocked for a moment.
"So you're..."
"Yeah...girlfriend" that sounded so juvenile coming out of her mouth, but it was the only word she could think of.  About that time, her phone rang.  "Hello?"
"Hey, on my way home"
"Hey.  Good to hear that.  We've got a visitor, or more accurately, you do..." she replied.
"Who is it? Should I be worried?"
"No, no need to worry.  It's an agent Fornell.  Sound familiar?" She heard a sigh on the other end.  "That a problem?"
"No...I'll be home in 5"
"Okay. See you soon" she ended the call and turned to the man.  "That was Gibbs.  He's on his way home.  Is there anything I need to know?"
"Not that he hasn't told you already..."
-next morning-
Grace got filled in on how the two men knew each other, and it turned out that Fornell needed NCIS help with a case.  He came into HQ at some point to go over his side of the case.  At some point, a red headed woman came into the corridor.
"Diane, what are you doing here?"
"I could as you the same thing! It's your day to watch Emily and as usual, you're working!"
"Hey, I'm doing my job.  What about the babysitter?"
"She cancelled." She turned to Gibbs.  "For the record, I blame you"
"Why me?"
"You agreed to help him with their little case." She replied.  All the while, Grace was literally just standing there wondering what was going on. 
"Excuse me, ma'am, can I help you?"
"Stay out of this"
"Hey! Don't talk to her that way! I get your mad at us, but don't take it out on her!"Gibbs said, overprotective nature showing through just enough that Diane figured it out quickly.
"Ah, I see...well, maybe you can help me then.  My name is Diane Sterling, formerly Fornell..." she paused for a moment, looking at Gibbs again.  "...and Gibbs" the way the color drained out of Grace's face told Gibbs that he was in trouble...