When Ziva told Tony about Tali's death, I couldn't help but wonder- how did it happen? And then this plot bunny presented itself to me.

AN - Ziva does not know about Ari yet.

A young Ziva walked down the streets of Tel Aviv, desperately searching for her younger sister. She had known that one day Tali would run away for some time in order to escape the vice-like grip her father kept on her, afraid that he would lose her in a terror attack.

But no one could find Tali, even though practically the whole of Mossad was searching for her. The Deputy Director of Mossad had told all his agents to pursue any lead they got, no matter how improbable it seemed, in order to find his favorite child. And whatever the Deputy Director of Mossad wanted was inevitably done.

As Ziva came near the main market area, she noticed a flash of short, asymmetrically cropped black hair. Very few people in Israel had that style of hair – her sister being one of the few who sported that particular one. As she looked closer, Ziva saw that it was indeed Tali who was approaching her.

She could feel her heart start to beat faster. Not just in relief but in anger. She knew that her sister sometimes felt stifled being in their father's control, but Tali could have at least told her where she was going - she would not have needed to worry so much. Suddenly, a blast sounded. She had heard that sound enough times to know what it was- a suicide bomber, a shaheed- blasting himself out of existence and taking as many people as he could with him in his misplaced hope of reaching whatever heaven he had been indoctrinated to believe in. There were too many such people who attacked her country and her people and they did so frighteningly often. But Ziva didn't see the terror being unleashed by the bomb. All she could see was her sister, close, so close to the suicide bomber. She may have been Mossad, but for all her training, she found herself riveted to the place, able to focus on only one thing- her sister being engulfed by the smoke from the fires of the bomb.

Terror gripped her heart, only to be replaced with mind-numbing relief when she saw her sister emerge unscathed, walking through from the smoke, seeming unharmed.

But before she could truly relax, within an instant, she heard another blast. A second suicide bomber. Her body froze, her mind filled with horror such as she had never known before. She watched, as if detached, as the fires of the bomb engulfed her younger sibling. Her mind kept on telling her that her sister was dead but still her heart refused to believe it. A silent scream kept running on and on in her mind – No, no, no, no, not Tali, not her Tali, not her, anyone but her, no, no, no, no……… Her body was completely numb, rooted to the spot in disbelief, unable to believe that her younger sibling, the person she loved more than anyone in the world, the only person she had left, was dead. She just collapsed on the ground, horror, shock and sadness washing over her. The terrible irony did not escape her - Tali had been lost to the one thing her father feared most- a terror attack.

She knew she shouldn't be surprised - it was common for more than one bomber to attack a single place together. But she didn't view it like a Mossad officer - it was different this time; it was her sister who had become a victim of the hate felt towards Israel.

And then she heard the sirens of the ambulances searching for survivors and transporting the dead to hospitals where their families could claim them, whatever was left of them. A badly burnt body was removed from the wreckage, miraculously alive. She needed no confirmation to know that it was Tali. She also knew that she was going to lose her; there was no way for her sister to survive this horrific second explosion.

She composed herself as well as she could and went over to say her last goodbye, knowing that she would not allow Tali to see her cry. Tali's breathing was labored and her face was contracting in pain but somehow she managed to breathe out her last words, words she knew her elder sister needed to hear.

'I love you Ziva. It wasn't your fault, it was just fate,' she managed to whisper out before her breathing became more and more labored, and her eyes closed for the final time.

And only then did she allow herself to collapse in tears, crying for her younger sister, for the girl she had almost single-handedly raised after their mother's death, for her best friend. But she also cried for herself, because she would never see Tali open her eyes again, would never hear her talk to her again or hear her say she loved her. And as her tears stopped falling, she found herself hating the fate that had caused her to be separated from the girl who was her whole world.

And every time after that day, whenever she thought of what had happened to her Tali, all she could see was the explosion of the second bomb, the fiery orange-red-gray-black flames and fumes, and the sight of her baby sister breathing her last. She did also remember all the laughter and the joy, the lovely times spent with her sister, the great love that she held for Tali, but sometimes the memory of her death was all that would come to her. Everyone around her told her that she should remember the good times and not to let Tali's death kill her too from inside.

But the remembrances of the good times made the memory of Tali's untimely death that much harder to bear, and the fires of revenge burned brighter inside her. She knew that the road she was about to take was a road that either destroyed all those who traveled upon it or forced them to turn back, when they found that they had lost more than they gained by walking upon it. Even then, she could not let the memory of her sisters' death, the desire to avenge her, fade away – Mossad became a way to wreak vengeance upon those who had destroyed her life. And though she knew Tali would not want it, she started to build barriers around her heart, barriers that only grew stronger with time, thus shutting nearly everyone out of it.

In later years she became what Mossad wanted her to become, trained her to become, and people would come to say that she was a cold-hearted killer, an assassin with no feelings. But what they did not know was that it was Tali's death that had made that woman afraid of caring for another because she feared that they, like her younger sister, would also die. And she could not bear a pain like that again – once had been enough, she did not know weather she would be able to bear it again.

And because no one was able to break through her cold façade and truly understand her, she stayed like that until she was assigned to be a liaison officer to NCIS, where she met a new family, and though they were not able to completely heal her from the effects of Tali's death- nobody ever would- the hole in her heart started to mend bit by bit and the cold assassin that she had taught herself to be for more than a decade changed into the Ziva she had once been, before Tali's death.

AN2 - Ziva might seem a little OOC, but bear in mind she has just lost her sister.

Read and review...constructive criticism welcome. My first fanfic.