What's better than BFFs? Super sidekick BFFs! Katie can't wait to have Beth join her for sidekick training! Until . . . it turns out Beth might be a way better sidekick than Katie! And now Beth and Marie are hanging out all the time, Jess is acting super weird, and Katie still needs to tell her mom about being a sidekick. Oh yeah, and giant robots are attacking the city. So. That's not great. Can Katie and 217 super-unusual cats work together to save the city (and seventh grade)? Or is Katie about to be in super trouble?