I'll admit, it's been a long time since I read Hey, Kiddo, which is fine for reading this! It's not a direct sequel of his first graphic novel memoir, but it does reference things that happened in that book and it does give you some background on his life leading up to this moment. 

This story is a look at kids who are going through traumatic experiences, who just want a chance to feel like normal kids at a summer camp. Given the subject matter, it's no surprise how emotional this book gets at the end, and Krosoczka does give some insight as to where some of the kids he met at camp end up. It's one of those graphic novels that will definitely leave you thinking long after you finish it.