Season two covered the second and third volumes of Oseman's novel, so the third season will potentially cover parts of volumes four and five. Volume four, released in January 2022, follows Nick and Charlie during the summer and the start of a new school. A big part of the plot of the volume is Nick trying to support Charlie as he struggles with an eating disorder, which is referenced in season two. As for what happens in volume five, the book won't be released until this December.