Lexi and her younger brother, Kevin, are spending the summer in New York City with their colorful actress aunt while their father is away on his honeymoon with his new wife. Still mourning the loss of their mother, time in NYC should be a welcome change for Lexi and Kevin-assuming that the day camp they'll be attending isn't super lame.
But excitement finds Lexi and Kevin when, while waiting for their aunt in Grand Central in the famous Whispering Gallery, Lexi overhears a conversation about a big jewel heist going down. Once at Aunt Roz's, the siblings meet Kim Ling Levine in the building. Half Chinese, half Jewish, persuasive and all knowing, Kim Ling urges them to ditch day camp and dig into the more exciting mystery Alexi overheard in Grand Central. After several missteps and a run-in with a mischievous runaway can Lexi, Kevin, and Kim find out who's behind the jewel heist without getting into too much trouble themselves?