The ringing phone startled the three of them from their work. Where's Gibbs? Kate looked at the empty desk next to her.

Dunno. Shouldn't he have been up here by now? McGee looked up, confused.

Tony got up and started moving toward the empty desk and ringing phone. Don't ask me why, but I suddenly have a bad feeling about this. He started to grab the receiver, then hit the button for the speaker instead and answered in a fairly good imitation of their boss' voice. Tony decided to keep his answers brief until they knew more about her situation.

We need to talk.Sure, where? Kate grabbed a pencil, ready to write down any directions the other woman gave.

Leah's voice took on a slightly odd quality as she spoke. You remember that old place of ours. And that argument, it's all water under the bridge, so come alone, okay? The stresses on the words were subtle, but Tony was sure he picked them up.

On my way. In his confusion over her words he let his concentration slip, sounding more like Tony and less like Gibbs as he hung up the phone. He turned to his partner and asked, Did you get that?That was strange. What do you think she was trying to say? Kate was puzzling over Leah's sentence, while McGee reread the statement over Kate's shoulder.

'Old place of ours.' Wonder where that could be. McGee mused.

And an argument that's water under the bridge, too. Weird. Kate said, tapping her fingers absently as she thought.

Well, it all has to mean something to Gibbs. Tony was dialing the man's cell phone as he spoke. After two rings, he found himself transferred immediately to voicemail.

McGee noted the confused expression on Tony's face. What's wrong? He looked at the other two and said slowly, You don't think he would have tried to go after her on his own, do you?

All three nodded. Right. Let's see if we can figure this out. What exactly did Leah say?Remember that old place of ours. Did they have an old place together? McGee asked?

I don't think so, but she stressed the words remember' and old', so maybe there's something significant there. Tony mused. Maybe we're supposed to remember something old. Or something old about a place.

Kate gave him a look and he subsided while they thought. The three were silent for a few minutes, as they tried to find the significance of the missing woman's message.

What's getting me is the bit about the argument being water under the bridge. Kate's frustrated voice broke the uneasy quiet. She threw the pencil on the desk as she continued. Which argument? They've only had about about a dozen!

Yeah, no kidding, her lover agreed. How are we supposed to know which one they kissed and made up over? Suddenly something sparked in his eyes. Hold on, why throw that in? He played the conversation back in his mind one more time, hearing her lean on the word water'. Maybe it isn't the argument. Maybe the key is water. McGee looked between the other two. What does water... wait... Tony. McGee held up a finger as he turned back to his desk and shuffled through the papers.

What is it, McGee? Tony walked over next to him, followed by Kate.

There's something about water that's bugging me, something that Leah and Gibbs told us...The filtration plant, Tony said quietly, nodding as the pieces clicked. Thanks, McGee.Tony, are you sure? Kate was dubious. It seemed like a pretty big leap to make, even if the logic was sound.

Think about it, Kate. It's where the whole thing took place, where better for Ketterer to want it to end? Tony looked seriously at Kate and McGee.

And he would know that, too. She nodded at the empty desk.