"Goodbye, John."

It was, and always had been, of great comfort to Sherlock to know that, in time, John would come to understand why Sherlock had to leave him behind. However non-existent the reason seemed to John now, the doctor would one day come to see why Sherlock chose to do what he did. The certainty of this gave Sherlock the courage to see his plan through to the end. It always had.

You see, the process of John's recovery was nearly complete. Sherlock had been sent to heal John using 'The Five Lessons', and he had very nearly succeeded. Gone was the doctors' psychosomatic limp, his pessimistic outlook on life, his loneliness, and the nightmares which had previously plagued him so often had now been chased away by dreams which let him relive the doctor's improbable adventures with the detective.

Sherlock was now about to teach the final part of his fifth lesson for John: independence. Independence was something that John had not had for many years, and its loss had been detrimental for him. Over the last decade, the doctor had experienced dependence, interdependence, and even co-dependence with Sherlock himself, but not independence. Sherlock's mission was to heal John, and he could only complete this by giving the doctor everything he had been lacking.

You see, there is something which should be understood about the way Sherlock works. When you need him, but do not want him, he has to stay. However, when you want him, but no longer need him, then he has to go.

If the Fifth Lesson went to plan, John would no longer need Sherlock. He would want him, and the pain of the loss of Sherlock would pierce John's heart for a considerable amount of time, but he would no longer need him as he once did, and so he would be healed.

Sherlock took a deep breath and jumped, safe in the knowledge that this was not truly goodbye - at least not yet - and he would see John again.

After it was done, Sherlock watched from the shadows to ensure his work was complete before he could allow himself to move on to another who needed his help.

"Sherlock...I was so alone, and I owe you so much."

The words were spoken, and Sherlock observed as John walked away from his 'grave' limp-free after acknowledging that he would miss his friend, but he was no longer lonely. It was then that Sherlock knew for sure that his work here was done.

A sad smile crossed his face as he was disappeared into the distance before anyone could spot him - Sherlock hated goodbyes.