The world outside has grown toxic, the view of it limited, talk of it forbidden. The remnants of humanity live underground in a single silo. But there are always those who hope, who dream. These are the dangerous people, the residents who infect others with their optimism. Their punishment is simple. They are given the very thing they want: They are allowed to go outside.

The old world is buried. A new one has been forged atop the shifting dunes. Here in this land of howling wind and infernal sand, four siblings find themselves scattered and lost. Their father was a sand diver, one of the elite few who could travel deep beneath the desert floor and bring up the relics and scraps that keep their people alive. But their father is gone. And the world he left behind might be next.

At the end of the world, a groundbreaking scientific experiment will change everything. Dr. Laura Reynolds had it all. A job she loved. The respect of her peers. Student debt she was slowly chipping away at. And one day, it all went away. She saw the wrong thing—a colleague's mistake. And to escape, he framed her. Laura's only option is to join a secretive research project in Antarctica, where she hopes to keep practicing medicine and one day get her life back. But soon after arriving, she realizes that things aren't what they seem in this advanced facility.

At first, only a few things are known about the celestial object that astronomers dub Rama. It is huge, weighing more than ten trillion tons. And it is hurtling through the solar system at inconceivable speed. Then a space probe confirms the unthinkable: Rama is no natural object. It is, incredibly, an interstellar spacecraft. Space explorers and planet-bound scientists alike prepare for mankind's first encounter with alien intelligence.

For centuries, men and women have manned lighthouses to ensure the safe passage of ships. It is a lonely job and a thankless one for the most part. Until something goes wrong. Until a ship is in distress. In the twenty-third century, this job has moved into outer space. A network of beacons allows ships to travel across the Milky Way at many times the speed of light. These beacons are built to be robust. They never break down. They never fail. At least, they aren’t supposed to.