"How to 'play on' a surprise!" cried Billy. "Well, how am I to know
until I see it? I can play on 'most everything else!"

They had got to the little front gate--were going up the little
carefully-weeded path--were very close to it now. Billy sprang up the
steps.

"I can! I can!" she laughed. "Hear me!" Her fingers ran up and down the
keys, then settled into a soft, sweet little melody. Another and
another--

The old man on the lower step sat patiently listening and waiting. If
she did not play it soon, he should have to ask her to, but he would
rather have her play it without. Perhaps the next one--

The next one was beautiful, but not It--not _It_--not the Right
One.

"There!" finished Billy with a flourish. "You see, I _can_ play on
a surprise!" She stopped abruptly at sight of the disappointed old face
below her. For an instant she was bewildered, then a beautiful instinct
that had lain unused on some shelf of Billy's mind came to life and
whispered to her what the trouble was.

"Oh!" she cried softly, "Oh, I'm sorry I forgot!" She turned back to
the little organ and began to play again.

[Illustration: THE OLD MAN SAT LISTENING AND WAITING.]