Azure Miles and Roberta (Robbi) Holten are chosen to go to Laddertop academy. I school for select children who are small enough to maintain the web on Laddertop. The Givers, a mysterious alien race built the four ladders and Laddertop 25 years ago. It provides electricity to all of earth. Roberta did not submit her name, but she believes her mom did. Azure is extremely excited to go.

They begin their training, in zero g, and Azure excels. One night while taking a shower, Robbi has strange letters etched into her arm by an alien bug. A few days later, they enter the Scan, which is the final selection process for the candidates. Azure is rejected, Robbi is selected, but during the scan process, she receives a cryptic message about something to come that she doesn't understand. She tells no one about it and the writing disappears form her arm in the process.

Robbi arrives at Laddertop, where she sees a lever that has writing on it that looked like the writing that was on her arm. The Givers left instructions that the level must never be pulled, but the book ends with Robbi (in an internal monologue) declare she will pull it.