Prince Charles was acutely aware of the truth behind the theft of the black wooden box.
Including the moment when the Crown Prince stepped forward, using the accident during the transaction as an excuse, and demanding that Chen Tang return the key, whether his true goal was to help him recover the loss or covet the key, Prince Charles was just as clear in his mind...
It was beyond his expectations that the Dongying Prince, of such noble status, would stoop to such despicable and shameless depths. By now, Prince Charles had come to despise the Crown Prince deeply.
But with the black wooden box now in the hands of the Crown Prince, to reclaim it, he would still need to feign civility with the Crown Prince and look for opportunities.
Additionally, the key he had given to Chen Tang was nothing more than a replica, and Prince Charles couldn't care less about it.