Using the Key
As he attempted to unlock it, he discovered that the door was firmly secured. Momentarily perplexed, a recollection sparked within him – the letter had come with a key! Hastily rummaging through his pockets, he was relieved to find the key he had brought along. Eagerly, he inserted it into the lock and, with a sigh of relief, the door creaked open, beckoning John to take a deep breath before venturing inside.