*****

Their first astronomy lesson had been arranged for two evenings later, after dinner. They returned to the alchemy laboratory and unlocked the trapdoor that was on the ceiling; they climbed up the ladder and reached the terrace underneath the roof of the north tower. Adrien advanced towards the stone parapet so he could see the stars, but Val stopped him; "No, don't look at the view yet", he said as he locked the trapdoor. "Let me show you something".

He spun a spell of blue light with one hand, and he cast it upwards. The roof above them shimmered for a moment, then sparkled away, disappearing completely.