Katie is dreading the boring summer ahead while her best friends are all away at camp--something that's way out of Katie and her mom's budget, UNLESS Katie can figure out a way to earn the money for camp herself. But when Katie gets a job catsitting for her mysterious upstairs neighbor, life get interesting. First, Madeline has 217 cats (!) and they're not exactly . . . normal cats. Also, why is Madeline always out EXACTLY when the city's most notorious villain commits crimes?! Is it possible that Katie's upstairs neighbor is really a super villain? Can Katie wrangle a whole lot of wayward cats, save a best friendship (why is Beth barely writing back? And who's this boy she keeps talking about?!), AND crack the biggest story in the city's history? Some heroes have capes . . . Katie has cats!