-The solution-

  You approach the star sculptures and first look at the holes and then at the two spheres.

  You hesitate for a moment, but then you place the spheres in their reserved places and it does indeed seem to be correct. The magic shield on the gate disappears and you quickly climb back down to the ground.

  This tale has been unlawfully lifted from Royal Road. If you spot it on Amazon, please report it.

  After taking a deep breath, you step through the now open door. You have overcome the first hurdle!

  Now go to section 20 to continue with the next obstacle.