Dr. Jekyll and Mr. Hyde (Penguin Readers, Level 3): Robert Louis Stevenson

Mr Hyde has a frightening, ugly character. Why, then, is the honest Dr Jekyll such good friends with him? Mr Utterson tries to find out the secret power Mr Hyde has over Dr Jekyll but then Sir Danvers Carew is murdered and Mr Hyde disappears - or does he? As Mr Utterson tries to find the answers to these questions, he learns the terrible secret of Dr Jekyll's dangerous experiments.