The OG Twilight. Seriously, I had to go back and check ten years of internet ago to see if people were talking about this, and they were. The basic plot and set up for this whole world, though not being vampires, is Twilight. So Stephanie Meyer might owe Natalie Babbitt some money.
I think I might have read this one as a kid, but it also might just be in the aether of my childhood the way a lot of books are. It’s about a young girl who happens upon a spring in her family’s land, and find a 17 year old boy drinking from it. When she says hello to him he panics and covers up the spring. He says he’s 17, and when she presses him about drinking from the spring, he calls in backup from his family. They explain she has to go with them to their home, where they’ll explain. Turns out they’re immortal and the spring is the source of it. It happened by accident, but while the tone is more or less neutral, the content is dark on this one. They are IMMORTAL immortal, as in impervious to death it seems. They’ve had accidental deaths…not take. They’ve tried suicide and nothing happens. They’ve kidnapped her to truly press upon her the importance of her silence, not because they want the spring all to themselves, but because they’re tragic figures and no one would believe them until it’s too late.
But someone saw them! A villain!
But seriously this book is solid and holds up. It’s about life and its preciousness, seen from the other side.