Gamache believed people could change. For the worse, yes. But also for the better. But Jean-Guy Beauvoir knew better. People did not, in his experience, fundamentally change. All that changed was their ability to better hide their worst thoughts. To put on the civilized face. But behind the smiles and polite conversation, unseen in the gloom, the rot grew and grew, and when the time was right, when the conditions were right, those terrible thoughts turned into horrific actions.
