Henry needs to find The Silent One to summon the Beast.
Where do I start looking?
Where, exaactly, should I explore?
What's next?
I can't interact with anything inside the pyramid.
When can I wake them?
5 hints available
Where do I start looking?
Head back to New Callisto (by using the Star Map in the eye section of the inventory) and explore new locations, now you can ride Dorothy. If you can't ride Dorothy, use the hints for getting a ride from Dorothy.
Where, exaactly, should I explore?
Travel to the Sunstone Pyramid. (You can ask Wrangler for a ride on Dorothy.)
What's next?
You can climb the steps up the left hand side to the Hidden Entrance. If you can interact with things inside, the next lot of hints are about understanding the Musical Instruments.
I can't interact with anything inside the pyramid.
If you interact with a Disciple and they shoosh you with their finger, you can't wake them, as yet.
When can I wake them?
I'm honestly not sure. For me, it appeared to happen after I looked at the Strange Symbol next to Spflornk of Pluto, or possibly when I dealt with the Vines, but neither of those make a lot of sense as to why that would be. If you're not sure, touch the Veiled Instrument (?) again as you solve more puzzles.