Harper Lane has spent her whole life being “Noah’s little sister.” Quiet, bookish, and easy to overlook—especially by Jace Carter, her brother’s best friend and the boy she secretly adored since they were kids.But after a summer abroad in Italy, Harper comes home different—confident, grown-up, and no longer the shy girl Jace used to tease. What she doesn’t expect is to find him half-naked in her bedroom.When she discovers her brother let Jace stay in her room while she was gone, things get complicated fast. Because now, Jace can’t stop noticing the way she smiles, the way she moves, the way she’s become something he can’t have.He swore he’d never cross that line. She swore she’d never tell him how she felt.But when Harper, an aspiring romance writer, asks him for “research help” with her new book—lessons on what kissing and s*x actually feel like—their fragile boundaries start to blur.What starts as innocent “research” turns into something dangerous, addictive, and completely off-limits.Because she’s his best friend’s sister.And because falling for her might ruin everything.A steamy, emotional slow-burn romance about first love, jealousy, and the one person you’re not supposed to want.