With mystery

The piano music arrived and I've been playing the last few hours. It's been wonderful - not too easy, but not that difficult, and it sounds so nice. I bought the book for one song. I've blipped its intro - can you guess what it is? I admit that I've never before had the instruction to play 'With mystery', but I did my best. It involved lots of skulking gestures across the keyboard, and playful eyebrow gestures, of course. If only I had a tail!