This could be a teeny bit spoiler-y, so
The titular Ramona Blue, who by the way is 6'3 and dyes her hair blue, had been an out lesbian since 9th grade. Her whole world is her sister Hattie, her dad, and Ruth and Saul the gay kids she works with at a seafood restaurant. That's just one of her jobs. She also has a paper route to supplement her family's glamorous trailer park life. Hurricane Katrina was not kind to them when they lived in New Orleans. It cost them their home, and their mom. She didn't die; she just stayed in NOLA when the rest of the family moved to Eulogy, Mississippi. Other towns in the novel are Picayune and something else super quaint and evocative. Oh, Ramona has one other person in her life--Grace, who she wasn't supposed to fall in love with (no tourists!), but did. Luckily around the same time Grace goes back to Picayune (or the other quaint/evocative name town), Ramona's old friend Freddie and his grandmother come back to town. Freddie is also doing the long-distance thing with his girlfriend Viv from the quaint/evocative name town (or Picayune). GUESS WHAT HAPPENS. What I LOVE is that Ramona has to question her sexuality because she's attracted to a dude.
btw Freddie is Black, and Ramona has some lessons there. Given the names Ruth and Saul, I'm guessing those two are Jewish, but they don't fit stereotypes any more than Freddie does. Murphy (a librarian!) thanks multiple friends for "sensitivity reads," which I think is nice, but if Ruth and Saul were meant to make Jews feel seen, I don't think it worked. I do feel like she did a good job with Black characters.
More than anything, Ramona Blue is a coming-of-age (dare I say Bildungsroman?) story. Ramona learns things about herself and is transformed by the end.