Tomb Raider: Atlantean Scion

Lara Croft is sent on the most dangerous mission of her life after being summoned by Jaquline Natla. She was sent to find the Atlantean scion; an ancient artifact that revealed the true history behind the rulers of Atlantis. When she finds it however, Natla takes it from her and returns to Atlantis to take her place as queen. Lara follows her and destroys the scion before Natla can persue her dream of controlling Atlantis.

This is the original game of the tomb raider series. There are many others: dagger of xian, the meteorite, last revolation, chronicles, angel of darkness, legend, anniversary and underworld. All these games have overviews like this one including extensive walkthroughs on my tomb raider site: tombraidergold.webs.com