Seasick by Kristin Cast

Ex–best friends Naya Morgan and Yana Bunpraserit have always felt like outsiders in their small Oklahoma town. But this year, everything changes when they’re inducted into an exclusive society of Yatesville High’s top recent graduates. Unimaginable opportunities await them, starting with a celebratory yacht trip to Bermuda. Despite the likely onslaught of microaggressions and backhanded compliments from their peers—in addition to their own rocky past—Yana and Naya are ready for an epic voyage.
Then one of their classmates is brutally murdered, leaving them stuck at sea with a killer. Yana and Naya may have avoided each other for years, yet as the body count rises, rekindling their friendship might be the only way they’ll both survive.