The back of my neck went cold. I stood confused, staring into the darkness. Jack, the only person I knew who could play the piano, was miles away, moored up on the broads. And Jack didn't play jazz. The music went on and on, faint and familiar, jauntily inviting me to move in time with it. There was a small delicious run of notes and then it came to an abrupt end. I heard the lid come down, followed by footsteps going out into the hall. The kitchen door opened and shut gently. Moments later the outside light came on. Instantly I was galvanised and rushed downstairs. But when I reached the back door the garden was in darkness once more.