Or maybe 3.5 stars. I did like it - Stead has a readable, funny style that's appealing, and her characters are quirky and real. I liked how she addressed bullying, and the loneliness that comes from feeling different and having parents who are often absent. 
 But it sometimes felt slow to me. While there is the plot of the kids spying in their apartment building, it didn't always feel like the story was moving forward.