Naomi Kritzer’s Chaos on Catnet is a direct sequel to her Lodestar Award winner Catfishing on Catnet, and it does exactly what a sequel should do: expand the stakes, introduce a few important new characters, reveal some secrets and puzzles left over from the first novel, and deepen the tone a bit. The trick is to manage all this without retreading familiar plot points or losing the authentically breezy YA tone of the first novel. Catfishing on Catnet managed to keep that almost sunny tone intact while developing some pretty dark plotlines: the teenage Steph and her computer-genius mom moved from town to town in an effort to avoid being tracked down by her abusive and even homicidal father, never settling anywhere for long and never giving Steph a chance to develop friendships. Her social life took place almost entirely with a group of mostly geeky friends on a website called Catnet, which is actually managed by one of those friends, who (we learn) turns out to be a powerful AI calling itself CheshireCat, and who basically just wants to look at cat pictures and help out her new friends.