The title character in this pocket-size musical by Greta Mae Productions is the imaginary friend of eight-year-old Lucy--a relationship eliciting the jealous disapproval of her mother, who's long since ceased believing in fairies of any type. The metaphors in Joe Latessa's hour-long fairy-tale opera, using a score dominated by waltzes, prove elusive. But in this intimate space, under Jim Glaub's direction, the show does create humor and empathy. Intense performances by Kristen Freilich as the embittered mother and Ashley Bush as the lonely child (Elaine Robinson played the larder-dwelling sapphist on opening night) spurred hearty applause when the women eventually decided to forge on together. Through 11/21: Fri-Sat 7 PM, Sun 2 PM. Athenaeum Theatre, first-floor studio theater, 2936 N. Southport, 312-902-1500. $15.