The Broken Teacup

Katie Bonner needs a pick-me-up one cold and gloomy fall day, and the US Mail delivers--literally. A mysterious package arrives at Artisans Alley with her name on it, but the return address is obscured and the treasure inside, a beautiful bone china teacup, is broken. Before Katie can open the accompanying card, she's called away and one of the vendors mistakes the package for trash. Katie makes a quick rescue, but the card is gone. Who sent the cup? What is its significance? Can Katie solve this mini mystery?