Joly sighs. "That's a very good question. Monsieur Gringoire told me the three of you had been conducting an experiment, which went a bit out of control. It may have caused this. But whether it--deaged your adult selves, or simply switched your places in time, or something else--I really can't say."

He looks between the boys. "Would you be willing to let me examine you both in the Infirmary? Nothing painful, I promise. But I might be able to at least rule some things out, there."