In the cut scene, following the coordinates that Natla gave her Lara reaches the Arctic Sea. She parks her bike and set an explosion device that blows up the ice, creating a big hole that leads to the ruins. Lara then dives into the water and swims past six huge Norse statues. She then enters a tower as the stone drawbridge closes behind her.

[Checkpoint] Swim forward until Lara surfaces. Climb out of the water and step on the stairs. Go up them, but before going through the opening, get the Treasure (1/4) from the niche in the right hand wall (as shown in this image). Go through the opening.

The cut scene shows Lara entering the next room. As she takes a look around, Natla flies down from above and lands in front of the glowing exit. Lara uses her videocamera and zooms in to take a closer look of what Natla is doing. The latter uses her power and rearranges the lock. She then smiles at Lara, who now has to complete the next part. Natla then flies and leaves the room.

[Checkpoint] Room with toxic pool - Proceed forward to the extended part of the ledge. You have to cross the toxic pool and reach the opposite side.

Crossing the pool - (The entire process is shown in this page.) Hang from the edge and drop to the lower ledge below. Turn around and equip the Hammer. A Yeti thrall rises up from the water, so blast it. Facing the pool, approach the left side and carefully step on the pipe. Walk to the other side where you will reach a small ledge. Pick up the Treasure (2/4) and step back on the pipe.

Halfway through, stop and turn left. Jump to grab the low wall and traverse to the right. Then jump to the small ledge in the middle of the pool. Alternatively, cross the pipe back to the ledge where you first dropped down and jump to the small ledge in the middle of the pool. Make sure you let go of the Left Analog Stick whilst in midair to avoid running past the ledge and fall into the pool.

Turn to face the other low wall (to the right if the entrance is to your back) and jump to grab it. Traverse to the left and jump back to grab the tall vertical pillar behind you. Climb almost to the top and jump to grab the nearby flat ledge. Pull up.

Turn right and take a look above to spot a metal ring. Use the Grapple to catch it and jump off the ledge. Swing and jump to grab the lowest of the handholds on the opposite wall. Jump up twice to grab the edge of the alcove and pull up. Pick up the Treasure (3/4) and walk back to the edge of the alcove. Use the Grapple to catch the same metal ring and swing back to the ledge.

Turn right and jump to grab the tall vertical pole. Slide to the bottom and equip the Hammer. Two Yeti thralls rise up from the pool, so take care of them. Facing the exit, approach the right hand side of the ledge. Jump to the small ledge ahead, then the next one. Pick up the Treasure (4/4) and make your way back to the ledge where you killed the tralls.

Facing the exit, approach the left side of the ledge and jump on the pipe. Walk to the other side and jump to grab the edge of the wall. Traverse to the right and pull up. Jump to grab the ledge ahead and pull up. Then approach the exit door.

In the short cut scene, Lara uses Mjolnir to open the door.

[Checkpoint] Through the exit - Go through the exit and follow the hallway around to the right, then left. Go down the four flights of stairs and kill the two Yeti thralls in the next hallway. As you turn around the next corner to the left, kill one more Yeti thrall. Then follow the hallway to the end.

The cut scene shows Lara entering the next room. She takes a look at the feminine figure that is standing in front of a falling water and recognises the silhouette. "Mother?" shes asks. As she approaches the woman she continues "Mother? It's me. It's Lara." The woman turns her head towards Lara and it's Amelia Croft, Lara's mother. But when she turns around, Lara steps back and cannot believe in her eyes. Her mother has turned into a thrall after all these years trapped in Helheim. Amelia approaches her, but Lara is trying to convince herself that her mother is dead so as to take the difficult decision. She points her gun towards her mother and says "My mother is dead. My mother died a long time ago." She takes a final look at her mother and says "You're not my mother." Just before Amelia reaches her, Lara Lara shoots the thrall until it falls into the toxic pool.

Lara kneels, obviously disappointed from the result. Natla arrives and confesses that she set Richard Croft on a quest to search for his wife so she could find the way to Helheim. But he betrayed her in Thailand and she killed him. When Lara appeared with Thor's Gauntlet, she used her in order Lara to continue her father's job which would lead Natla to Helheim. Lara takes out Mjolnir, the only weapon that can stop Natla. Before she uses it, the doppelganger appears from behind and grabs her, knocking the Hammer out of her hands.

"When I made this creature for Amanda," Natla explains, "she had no idea that my true purpose was to have the means to destroy you at this very moment." She also admits that both Lara and Amanda were mere actors in her play. She has a serpent to raise, so she leaves.

Lara and her twin start to fight, but the doppelganger throws Lara on the floor and grabs her neck. As she tries to choke her, Amanda appears from behind and uses the power of Wraith Stone to stop the creature and throw it into the toxic pool. Lara is amazed, but Amanda comes to explain that she wanted to let the creature finish Lara off, but the Midgard Serpent will tear the world apart and the only thing that can stop the disaster is Thor's Hammer.

Three Yeti thralls come from the hallway and Amanda tells Lara to go for the job since she can hold them off. Amanda tries to stop them and Lara is now after Natla.

[Checkpoint] After the cut scene, turn left and follow the hallway with Mjolnir equipped. Turn around the corner to the right and kill the Yeti thrall. Go down the stairs and kill one more thrall in the next hallway. Roll through the opening at the bottom of the fallen rocks, then roll through the next one. Then follow this long, boring hallway, going down the stairs you meet. You will finally reach an opening that you have to go through.