KISS Series #01 To Isandro Caesar Valdez, Sienna Elisia Salvacion has always been just his best friend's little sister-a girl he's sworn to protect, not fall for. But when she reconnects with her ex-high school sweetheart, Sandy begins to notice things he never did before: the way her laughter lingers, the quiet pull of her presence, and the uneasy sting of seeing her with someone else. As a third-year college student juggling the mess of academics, friendships, and his own not-so-perfect life, the last thing Sandy needs is more confusion. But the feelings stirring inside him refuse to stay buried. What started as a nagging ache grows into something impossible to ignore, pushing him to question everything-about Sienna, about himself, and about the love he thought he understood. Sometimes, the things we fight hardest to deny are the ones we've known all along.