Mediterranean Sea Section
Lara's notes for the Mediterranean Sea Expedition are as follows:
- My father died in a tragic accident while searching for Avalon, the mythical resting place of King Arthur. I never shared his belief that it had played any role in my mother's disappearance, but recent events make me suspect otherwise. Professor Eddington knew the coordinates Father intended to investigate next, but did not know how he had determined them or if he had confirmed the existence of a ruin at the location. That's up to me. 
- Main article: Tomb Raider Underworld Story#Mediterranean Sea
Lara's search for Avalon, and the truth of her mother's fate, begins in the Mediterranean Sea after she receives advice from Professor Eddington, a former associate of her father. Entering an elaborate undersea ruin, she finds engravings that apparently reveal it to be Niflheim, a location from Norse mythology. "Not Avalon exactly," Lara muses, "but the Norse equivalent."
At the heart of the ruin of Niflheim, Lara encounters an imposing statue of Thor, son of Odin, and a pedestal bearing a single ancient glove. She speculates that this may be one half of Járngreipr, the iron gauntlets that enabled Thor to wield his hammer, Mjolnir. The glove itself crumbles at her touch, but a strange device remains; when placed on the back of Lara's hand, it glows with a radiant blue light. Before she can investigate further, Lara is ambushed by a group of mercenaries and knocked out cold. She regains consciousness to find the artefact taken, and to hear the mercenary leader convey the message that "Amanda Evert sends her regards" before he destroys the exit to the chamber with a well-placed explosive.
Locating an alternate escape route from the ruin, thereby foiling Amanda's apparent attempt at exacting a highly personal form of revenge, Lara returns to her yacht to discover a ship nearby. After climbing on board, she fights her way through a heavily-armed crew until attacked by the mercenary leader encountered in the ruins below. Their brief battle causes an explosion, killing Lara's opponent instantly and - we soon learn - scuttling the vessel.
As Lara presses forward, she overhears a conversation between Amanda and another woman imprisoned inside a glass tube. Amanda is frustrated that the gauntlet device retrieved by Lara does not seem to function. In a significant, though subtle, moment, her caged companion informs her that the object had "bound" itself irrevocably to Lara. Learning that the ship has taken on water, Amanda departs, leaving Lara face-to-face with Jacqueline Natla: the Atlantean queen encountered in Tomb Raider and Tomb Raider Anniversary.
Natla greets Lara casually, entirely unsurprised by her arrival. Confirming that the portal that caused the disappearance of Amelia Croft was part of an ancient transport network, she reveals that Lara's father Richard had found the "wrong Norse underworld". Lara's mother had apparently travelled not to Niflheim below, but to Helheim. To gain access to Helheim, Natla informs Lara that she'll need to find Thor's hammer - and that search should begin in Thailand.
- Tomb Raider Underworld, Journal