The Magnificent Lizzie Brown and the Fairy Child by Vicki Lockwood
The Magnificent Lizzie Brown #4
Perfect condition
 
When the circus arrives in Edinburgh, Lizzie finds herself in competition with a fraudulent medium and in the process meets the local wealthy mill owner and his very young orphaned niece Amelia, who becomes enthralled by the magic of the circus--and when Amelia disappears during a "fairy hunt" while Lizzie was watching her, she finds herself under suspicion and needs to use her own visions to find the kidnapper and save the child.