Katie is dreading the boring summer ahead while her best friends are all away at camp—something that’s way out her mum’s budget, unless Katie can figure out a way to earn the money herself. But when Katie gets a job catsitting for her mysterious upstairs neighbour, life gets interesting. First, Madeline has 217 cats (!) and they’re not exactly … normal cats. Also, why is Madeline always out exactly when a notorious villain commits crimes?! Is Katie’s upstairs neighbour really a super villain?