This walkthrough is meant as a general guide only. It may not include every pickup or secret. There may also be alternative ways of approaching situations within the game.
This level begins with Lara sliding into a small moss coloured cave. Follow the corridor left and pickup the flares in the right hand corner. Slide down the ramp to land in a pool below. Swim north against the current and pull the underwater switch under the outcrop in the north wall. Swim south and pickup the large medipack on the left near the east wall. Swim through the newly opened gate at the end. Swim left and surface at an air pocket just before the two large pillars. Follow the corridor around and enter a darkened crawlspace in the north/east corner. Light a flare and crawl until you can stand up. Pickup the large medipack on the left near the west wall. Turn around, follow the corridor on the right and watch a cutscene as you approach the area ahead. Arm weapons and shoot the two crocodiles. Enter the water-filled area past the first pool and head to the right. Swim into a crawlspace under an alcove and surface in the next room.
Climb out of the water via one of the shallow blocks and take a standing jump and grab to the next block. Face the rope and take a running jump and grab the rope. Angle to face the right side of the east wall, swing and grab the climbable wall while avoiding the spikes. Shift right until you can drop into the alcove. Follow the corridor and drop into the hole. Shoot the vase and pickup the Uzi ammo. Pull the wall switch and exit through the stone door on the left. Swim left to head back to the crocodile pool. Swim back through the same underwater crawlspace to surface back to the room with the rope. Climb the blocks to the top but this time aim for the left side of the climbable wall, swing and grab. Shift left until you can drop into the alcove. Follow the corridor down several blocks until you reach an opening behind a waterfall. Take a running jump to the pedestal and pickup the Golden Star. Immediately drop into the water as a fire wraith tries to torch you. Swim back through the underwater gate in the south wall and make your way back to the crocodile pool.
Swim back to the same underwater crawlspace but this time pull up into the alcove above. Follow the corridor around and take a running jump over the gap to the block on the other side. Drop down and follow the corridor to the end. Turn around, jump back and grab the edge of the opening where there is a climable wall. Climb to the left until you reach the ledge behind the waterfall and drop down. Push the floor lever and watch a cutscene of a large circular stone door opening in the croc pool area. Head to the edge of the waterfall and jump up and grab the south wall which is also climbable. Climb left, around the corner until you reach another ledge and drop down. Enter the door on the right and safety drop down. Enter the room carefully and take a standing jump to avoid the spike tiles in the floor. Pickup the Uzi ammo and follow the corridor to the next area.
Turn around, slide down the slope and grab the edge. Shimmy to the left to the end and take a backflip off the slope to the block in the water below (some loss of life). Turn around and shoot the crocodile in the water. Take running jumps and grabs to the blocks ahead until you reach the one in the north/east corner. Turn left and take running jump to the ledge. Climb the next block and turn around. Jump up and grab the ledge and pull up. Head around the ledge to the right. Take standing jumps to avoid the fire tiles and pickup the Golden Star on the pedestal. Immediately jump into the water and swim to the small underwater crawlspace in the south/west corner. Swim through the beige corridor and two gates trap you in the middle of an intersecting underwater corridor. Swim left towards the blue sun symbol and surface. Pull the statue from the wall and jump up and grab the jump switch on the east wall. Head back to the edge of the water hole and angle left. Take a standing jump into the alcove above and pickup the small medipack. Drop into the water, swim to the "scorpion" symbol and pull up.
As soon as you enter four swarms of beetles emerge from each of the four corners of the room. As quickly as possible, make your way around the room and pull each of the ten wall switches. Pickup the Golden Star in the middle of the room and the gate beneath opens. Surface for air and let the beetles fall into the water. Pull up back into the room and pickup the small medipack in the south/west corner. Drop back into the water and swim down the corridor. About half way through, swim right and pickup the Uzi ammo on the floor of the underwater room. Surface for air, then go north back through the underwater corridor to the large atrium area. Swim right, through the underwater crawlspace and surface back in the crocodile pool. Swim to the rows of columns on the right, climb the stairway and turn right to a platform with 4 Star receptacles. Head to the south part of the platform and take a running jump (and grab to change trajectory) to a semi-concealed corridor behind the waterfall. Head down the corridor and turn left into the next area.
Climb the stairs and shoot the large vase on the right. Pickup the Uzi ammo and immediately run through the door, into the water as a fire wraith follows. Head through the door and it closes behind you. Dive into the water and pull up onto the block in the middle of the room. Reverse roll, dive back into the water, swim back to the ledge and pull up. Arm weapons and shoot the crocodile in the water. Dive back into the water, climb the block and pickup the Uzis. Arm weapons and shoot the Minotaur Guardian (dropping into the water behind the block when necessary to avoid his blasts). Pickup the Guardian Key left behind by the Minotaur and head to the back of the room, behind the glass wall. Pickup the Golden Star on the pedestal. Immediately jump back to avoid the blades that emanate from the pedestal and return to the ledge on the other side of the room. Place the Guardian Key in the receptacle and exit. Turn right down the corridor and take a running jump back to the platform.
Pickup the small medipack on the left near the skeleton. Place all four Golden Stars in the receptacles and another large circular stone door opens in the west wall. Immediately run through the newly opened door and climb the ladder as two ice wraiths pursue. Near the top of the ladder, backflip and climb to the next ledge. Continue to the top, run forward and the level ends.