Scorpion

In Scorpion, the sequel to Jeff Sweat's YA futuristic thriller Mayfly, Jemma, Lady, and Pico all left the Holy Wood to seek answers to the End, and when they find the Old Guys—the only adults to have survived the original wipeout of everyone over the age of seventeen—they think they've found help at last.

But there's a lot the Old Guys aren't telling them. In fact, some of them don't seem interested in solving the End at all and just want Jemma and her friends to leave. Meanwhile, war is brewing among the tribes of the rest of the Children. Jemma's old home has fallen into disorder, and is far from prepared for battle. It won't be long before the fighting reaches Jemma and the Old Guys, if they even live to see it.