Hey there!
This is around the scene where seemingly kind Mr. Tumnus pulls out his flute. He plays a happy tune and the tune is so beautiful to Lucy, she sits there almost as if she's startled, surprised, and amazed at the same time.
However, within seconds all of this diminishes. Lucy realizes that her siblings will all miss her and notice her unprecedented absence, and become worried and go looking for her. Mr Tumnus promptly beings to cry, and that's when Lucy hands him a D, handkerchief.
Hope this helps!
