Laddertop

An original science fiction tale by the bestselling author of Ender's Game and his daughter Twenty-five years ago, the alien Givers came to Earth and bestowed upon the human race the greatest technology ever seen-four giant towers known as Ladders that rise thirty-six thousand miles and culminate in space stations that power the entire planet. Then, for reasons unknown, the Givers disappeared. Due to the unique alien construction of the Laddertop space stations, only a skilled crew of children can perform the maintenance necessary to keep the stations up and running. Back on Earth, competition is fierce to enter Laddertop Academy. It is an honor few students will achieve. Best friends Robbi and Azure, two eleven-year-old girls who are candidates for the academy, will become entangled in a dangerous mystery that may help them solve the riddle of the Givers-if it doesn't destroy the Earth first.

Basic training is over. For eleven-year-old Robbi, the real work on the Laddertop station begins... even as its strange, dark secrets grow more compelling. With the help of mentally-linked robot companions, she and an elite crew of children perform the dangerous maintenance work on the Power Web. But only Robbi keeps having urgent dreams from The Givers, the alien species who bestowed upon humans all the Laddertop technology. Meanwhile, her best friend Azure goes from Laddertop reject to a recruit for a secret research mission, led by a group of rebels who don't trust that the Givers mean no harm. Though on different paths, the two friends' destinies soon collide, as they decipher an alien message and solve an ancient mystery that could either save the Earth from invasion... or trigger its imminent destruction.

All seems lost as a giant comet hurtles toward Earth, while Robbi's Laddertop is thrown into chaos by the unleashing of Energy Spiders that now prowl the Power Web. As Robbi races against time to save the Laddertop and reveal its final secret, Azure and the rest of her research team discover the horrible truth about the comet and the existence of a different, malevolent group of aliens: The Takers. It's up to these brilliant children to work together, using their special gifts and the unique bonds they share, to find a way to stop the end of the world before it's too late.