Feeling cast off when her best friend outgrows their shared love for a favorite celebrity, Cath, a dedicated fan-fiction writer, struggles to survive on her own in her first year of college while avoiding a surly roommate, bonding with a handsome classmate who only wants to talk about words and worrying about her fragile father.

In his first journal, middle schooler Rowley Jefferson, Greg Heffley's sidekick, records his experiences and misguided decision to write a biography of Greg, who, in his own mind, is destined to become rich and famous.

When they learn that a famous author is coming to visit Treetopolis, Eva and her classmates are assigned to write stories to share with the author, but Eva is so worried about her missing pet bat that she cannot think of anything to write.