[Being out and about for his daily walk (and without Sebastian, no less) means he's caught in pitch dark once all the lights extinguish, acting like this world's calling card for shenanigans. Of course, it would be Ciel's luck that this happens while Sebastian is off seeing to one of his other duties. It's not his job to carry candles on him just in case (that's Sebastian's job), and neither is he prepared for the lack of sight (again, Sebastian's job).
What he does do though, is follow the eerily glowing lights all the way to the Sakura tree, where it occurs to him that those lights are words, pulsing like several heartbeats and covering the whole surface of the trunk like some confessional lattice work. Dozens of phrases fading in and out, as if the Sakura tree is bearing the heart of this place.
Ciel watches this all, fascinated by this ever increasing train wreck of secrets, spotting a few that might be his own among the confessions.]