LARA OF ARABIA
There is a time period between the events of TR4 and the events of AOD that Core Design named 'Lara of Arabia'. This period of time was never meant to be shown, explained or playable in AOD. You would only catch glimpses in cutscenes and things that link to it.
Somehow Lara had escaped the pyramid. A nomadic tribe called Bedouin was passing by and took her into their village. There she met a shaman, a woman called Putai. She was a healer, she had gifts and she would use them to heal Lara. She gave her an Amulet of healing powers. Lara would have traveled with them along the ancient routes of North Africa, she had become one of them despite her name remaning unknown to them. Then one day she disappeared somewhere in the coastal areas of the Mediterranean.
Von Croy actually followed the trail of this tribe when he was still looking for Lara in Egypt. While he didn't learn anything about the shaman, he did hear about the Legend of El Hawa (which means desert wind). It was the story of a mysterious woman that would appear in approriate times to fight the aggressors and protect the nomadic tribes. Von Croy followed the traces of the legend and found himself in a desert oasis. There he found Lara. She appeared different, much stronger but she wasn't angry at him for leaving her. It seemed to Werner that Lara had been traumatized by her near-death experience.
The friendship she had found among the people of the desert gave her an insight that was missing in her life. In here she could use her skills for a greater purpose than her days of sporting for artifacts. Von Croy was unable to convince her to return to her former life. The Lara he once knew was dead. He gave her her backpack and left.
One day the tribe that saved her life was attacked and massacred. Lara left Africa and returned to England. Lara did not attempt to reconnect with old friends. She couldn't get over the fact that she had failed to protect the tribe and had lost the meaning in her life she once found in the desert. Then she received a call from Paris..
Source:
http://www.tro-online.com/tr6-scenario.html