A plane carrying nine-year-old Lara Croft and her mother Amelia crashes in a fierce storm while flying over Nepal, leaving the Crofts as the only survivors. While taking shelter in an abandoned monastery, Lara discovers a stone dais with an ancient sword set in it, which activates a dimensional portal when she touches it. Amelia intervenes and removes the sword, triggering an explosion that consumes her. Devastated, Lara sketches the dais in her journal so she can study it.
Years later, Lara, now a veteran explorer, travels to Tiwanaku, Bolivia, in search of a similar dais. To her surprise, a group of mercenaries have already located it. Their leader, American playboy James Rutland, questions Lara as to what she knows about a mysterious fragment recovered from the site and mentions that "Amanda" led him to it. As Lara tries to process his words, Rutland escapes and orders his men to kill her, but Lara is able to eliminate them.
Lara returns to a condemned dig site in Peru, where she recalls an incident that occurred several years earlier: while excavating a remote burial ground, Lara's team accidentally awakened a malevolent fire spirit, resulting in the deaths of everyone except for Lara and her partner Amanda Evert. Amanda managed to seal the entity in a jewel, but was subsequently left for dead in a cave-in. Entering the tomb once more, Lara uncovers the remains of Tiwanaku's last queen, as well as a replica blade similar to the one Rutland described. She theorizes that the weapon in question is actually Excalibur – part of the King Arthur legends – and that Amanda, having escaped death, is working with Rutland to find and reforge the sword's fragments.
Having deduced that the second is in the hands of Yakuza boss Shogo Takamoto, Lara sets up a meeting with him in Tokyo. Negotiations quickly falter and Takamoto retreats to his penthouse, where he tries to kill Lara with the fragment's power. After defeating him and claiming her prize, she then heads to Ghana, where Rutland's soldiers are searching for the Ghalali Key, a device needed to reforge Excalibur. Rutland corners Lara in the heart of the temple, but Lara easily beats him and takes his fragment. Meanwhile, Amanda raids Croft Manor looking for information on the next fragment. She learns that it is somewhere in Kazakhstan and heads there, with Lara in pursuit.
Following her trail, Lara enters a Soviet-era lab, where she learns how the Russians tried and failed to weaponize the fragment. Amanda reveals herself and explains that she survived by harnessing the power of the fire spirit, which she summons to kill Lara. Using the lab's experimental equipment, Lara forces it to self-destruct and escapes with the fragment, as well as a shield belonging to Sir Lancelot.
Following a map on the back of the shield, Lara's search brings her home to Cornwall, England. She discovers the real King Arthur's tomb hidden under a fake one in an old museum, with the final fragment stashed under his body. After besting both a sea serpent guarding the tomb and mercenaries sent by Amanda, Lara returns to her home to figure out how to reforge Excalibur. She realizes that the Ghalali Key is in fact a pendant belonging to her mother, who had it with her when the plane crashed. Lara searches the wreck and finds the Key. She then proceeds to the temple where her mother vanished and uses the Ghalali Key to restore Excalibur. She attempts to reactivate the dais, but it crumbles into nothing.
Recognizing that the dais in Bolivia is the only one left, Lara confronts Amanda and Rutland. Wielding the blade, she easily kills the latter and what remains of his forces. A furious Amanda takes direct control of the fire entity and attacks Lara. In a pitched battle, Lara separates them and destroys the entity. She then activates the dais and is confronted with a vision of her mother in Nepal. Realizing that she is looking directly into the past, Lara tries to warn her, but Amanda panics and tells her to remove the sword, causing the explosion that apparently kills Amelia.
Having learned the bitter truth that Amanda is ultimately responsible for her mother's disappearance, Lara threatens to kill her. Amanda explains that Amelia Croft is very much alive, having been transported to Avalon, the final resting place of King Arthur. Lara responds by knocking her unconscious and setting out to rescue her mother, triggering the events of Tomb Raider: Underworld.
Legend has the longest score of the series. It took nine months for Crystal Dynamics' in-house composer Troels Brun Folmann to finalize the composing process. Over three hours of raw material resulted, becoming four and a half hours of in-game music via a process called "micro-scoring", which is the idea of chopping the score down to very small components and triggering them in a way that compliments the game experience, including looping cues and individual accompaniments to cinematic scenes. All material was produced using software and Folmann's personal soundbanks
All levels in the game were scored individually. When Folmann began composing the soundtrack much time was spent investigating the native sounds and instruments of the different locations' environments and cultures. He wanted to have a specific musical timbre for every level, so he had to understand the musical influences of each individual part of the game. During the Tokyo level the player will hear roaring taiko drums and the Japanese shakuhachi flute, while playing in Bolivia pan flutes are prominent, and Ghana presents a variety of African percussions. Use of Nepalese instruments in the first Tomb Raider film's soundtrack by Graeme Revell also influenced Folmann's music for the Nepal level.
All the cinematics are scored with a symphonic orchestra in a more classical fashion; however, instead of recreating the atmosphere of a real orchestra, Troels employs the use of echoes for the orchestral sounds applied to his rendered software instruments.
Legend's title track starts off with the iconic Tomb Raider motif composed by Nathan McCree in 1996, played on an ancient middle-eastern ethnic flute known as the duduk. McCree's motif is incorporated frequently throughout the soundtrack. Following is a Celtic female voice, full choir and orchestra and a variety of different percussions. The main theme female voice sings a Scottish Gaelic traditional folk song named Ailein duinn, mostly known by Capercaillie's lead singer's interpretation for the Rob Roy movie. In 2006, Troels Folmann was awarded a BAFTA in the category 'Best original Score' as well as the GANG award, 'Music of the Year' for his work on Tomb Raider: Legend.