What is the synopsis for the play the curious case of Dr. Jekyll and Mr Hyde?

Jekyll was unable to find a necessary ingredient to make his potion. Ironically, Jekyll learns that this most necessary ingredient was in the first instance of his experiments, sullied. Subsequent supplies are pure and thus lacking the quality that makes the potion successful for his experiments. His ability to change back from Hyde into Jekyll slowly vanished. Jekyll writes that even as he composes his letter he knows that he will soon become Hyde permanently, and he wonders if Hyde will face execution for his crimes or choose to kill himself. Jekyll notes that, in either case, the end of his letter marks the end of the life of Dr Jekyll. He ends the letter saying "This is the end of Dr Jekyll. Goodbye... Good..." . With these Words, both the document and the novel come to a close.