Upon entering the cave, be ready to encounter a new type of enemy. Luckily it's just a plain Scorpion, nothing hard really. After the fight, go down the "corridor" and after you get to a bigger room look left to find a chest with a Phoenix Feather [!!!].
Fighting the Scorpions - as they always attack in groups - doesn't require any special strategies. Just equip a weapon with a big range (like the Claws of Hades) and begin the extermination. They always approach in a group and their basic attack is stabbing with their sting.
Fighting them is even easier than the undead dogs, as you can grab and kill them at any moment (as the dog only gets a kick).
On the end of the road there's a big gear. Turn it and the big lift will take you down. Once down, head forwards and through the dark corridor (use Helios' Head to light your way).
On your way you will be attacked by a group of Scorpions. Finish them off and enter the cave with hanging cubes.
Jump on the first one and begin the fight. You will be attacked by a group of armoured Cyclopes. Finish off the first two and another one will show up. There's also one without any armour between them, so focus on him first. Take control over him and get rid of the other enemies this way (the whole fight is rather demanding).
Afterwards take a look around. There are two chests with power-ups by one of the edges (a Minotaur Horn and experience, as you should have already maxed out one of the bars) [!!!] [!!!].
Now jump towards the tunnel and unveil it using Helios' head (there's a save point right next to it).
At the end of the unlocked path there's a partially flooded room. Before getting down, take a look around the platform you're standing on. There are two experience chests to be found there. Afterwards jump down and head right to find another chest with a power-up [!!!].
As you're down, there's a lever on the left side. Push it to rise up the water level and as a result you will be able to grab the grating on the right.
Climb up and head towards the lift, it's at the very end. Pull another lever to ride down.
This way you will find yourself in a dark cave. Move cautiously, as it's very easy to fall from the narrow wooden walkways. At the end of the road, jump onto the climbable wall.
As you reach the top, you will have to fight some Gorgons and Harpies. Kill them and head forward to reach a wall marked with golden footprints.
However before you Hermes' Boots, walk along the walkway to the end. There are two experience chests and one containing a Minotaur Horn to be found there [!!!].
Run up the wall and go through the cave in front of you (you will be attacked by a group of Scorpions but nothing more). Afterwards go through the corridor and open the door at the end.
This way you will once again arrive at the hanging cubes. Begin with looking behind the wall on the right, you will find an experience chest there. Afterwards head left and jump onto the nearest cube.
You will have to face a demanding boss. However before he shows up, a group of Scorpions will attack.
The first thing the big one will do is grab you. Quickly press L1 and R1 to break free (he will also use this attack later in the fight, not breaking free however doesn't kill you).
In order to defeat him, you have to attack his limbs on the left or right side - use the Cestus. The enemy will of course constantly try to hit you. If he rises up his abdomen, quickly jump back from him.
If you inflict enough damage and destroy all the crystals on either side, he will collapse out of exhaustion. Run up to his mouth and begin attacking him. After a couple hits a QTE mark will appear above his head - activate it and quickly press Circle to complete it.
The boss will leave the arena for a moment and the second phase will begin after he appears again.
During the second phase the fight will be almost identical, apart from a new enemy move. He might try to hit you with a freezing sting. Dodge it, as mere running won't do the job.
Once you destroy his last legs and hit his mouth a couple times, the last QTE will begin. It will be a little longer than the first one. At the beginning you'll have to press one of the basic buttons. Afterwards a flight sequence will begin [LS], during which you'll have to avoid falling ice blocks. Upon getting to the enemy, be ready to press one basic button and start turning the left stick [RS].
This way you will freeze the boss. Now you just need to shatter his body and then his abdomen. Pick up the item leaved behind - Boreas Icestorm. By obtaining it you will be able to manipulate the adjustment of the big cubes. Approach the big switch in the middle and interact with it. This way you will open up an air vent. Use it to fly up.
This way you will transported onto another switch. Before you interact with it, go to the end of the available road and turn left. There's a chest with a power-up there [!!!].
Interact with the next switch and afterwards do a couple jumps with hitting grapple points. During some you will be going in circles. Remember to let go as you get to another one.
Finish the series of jumps and you will land on a cube with another switch. Interact with it and you begin a fight. During it you will be attacked by shielded opponents. Takeout the Cestus do deal with them.
After the cube stops you will have to do some more jumps. Perform them and you will end up on a vertical wall. Climb it up.
Head towards the familiar area leading to the flooded room (passing a save point on your way).
After reaching the water interact with the previously unused switch and run up the vertical wall (also open the experience chest if you haven't before).
Afterwards head forward, go through the tunnel and get to Daedalus. After a short conversation, head right. There you will find two experience chests and one with a power-up [!!!].
Jump onto the rope hanging by Daedalus, go to its end and jump down onto the platform. Afterwards perform some jumps with hitting the grapple points (directions of the jumps will keep changing, so look out).
You will end up on a vertical wall, next to which there's a door. Use it to finish this chapter.