Little & Lion is a California dream of a book, a must-read for anyone who’s ever felt caught in between—places, people, identities, or two entirely different worlds.

Sixteen-year-old Suzette is home in Los Angeles for the summer after a year at boarding school in New England. Suz and her stepbrother Lionel have always been close, but their relationship isn’t as easy and effortless as it once was: Lion seems distant and unreadable, worried and frustrated that their old friends can’t see past the bipolar disorder he wrestles with daily. Suz desperately wants to repair things between them, but her feelings for Lion’s beautiful new girlfriend throw a wrench into the works. To make matters worse, Suz is the only one who knows Lion’s secret: he’s off his meds.

There’s so much to love about Little & Lion, but what really set it apart for me was its rich and fully-drawn cast of characters. Colbert writes teenagers—especially ones who actually act like teenagers—with such empathy and generosity, and everyone, from Suz’s best friend DeeDee to her kind, quiet almost-boyfriend Emil, sings more than one note. Race, religion, sexuality, and illness all are explored with subtle deftness; the result is characters who feel realistically complicated and ferociously alive.

I kept coming back to words like that—deftness, nuance, specificity—when I was thinking about how to describe Little & Lion. In many ways this is a novel of quiet pleasures: lush, vivid language, sharp-eyed emotional honesty, and a deeply delicious treehouse makeout that had me holding my breath as I read.

Colbert’s use of setting is masterful—I found myself yearning for the creaky Victorians and taco trucks of her quirky, artsy Los Angeles—and her eye for detail is one of the best in YA. Her vivid renderings of deceptively simple images—a bottle of raspberry vodka, the careful preparation of a bowl of pasta, a book about the secret language of flowers—stayed with me long after I was finished. Little & Lion is smart, literary YA at its finest, and I am so, so excited to share.