Leo had understood it at five years old, when he refused Alex’s easy reassurances and demanded proof instead of promises.

Even Beatrice, at the very end, had brushed the edge of understanding it, when she finally said I was wrong instead of I was protecting you.

Alex had been the last to learn it, and he had learned it in the most expensive classroom there is, the one where the tuition is paid in missed years you can never get back.

But he had learned it.