And that was how a great scandal threatened to affect the kingdom of Bohemia, and how the best plans of Mr. Sherlock Holmes were beaten by a woman’s … - Arthur Conan Doyle

Now is the dramatic moment of fate, Watson, when you hear a step upon the stair which is walking into your life, and you know not whether for good or ill. What does Dr. James Mortimer, the man of science, ask of Sherlock Holmes, the specialist in crime? Come in!

He has considerable gifts himself. He possesses two out of the three qualities necessary for the ideal detective. He has the power of observation and that of deduction. He is only wanting in knowledge; and that may come in time.

By the way, Doctor, I shall want your cooperation.'
'I shall be delighted.'
'You don't mind breaking the law?'
'Not in the least.'
'Nor running a chance of arrest?'
'Not in a good cause.'
'Oh, the cause is excellent!'
'Then I am your man.'
'I was sure that I might rely on you.