Unfortunately, the chemfets in Derec’s body were asserting their presence, and he was rapidly getting weaker himself. With the help of R. David, an Earth robot, they stole a ship from an Earth spaceport and headed out to rescue Wolruf and Mandelbrot.

Another spaceship followed them: Aranimas, who had tracked the bursts of Key static to Earth. In a tense battle, Derec and Ariel, with Mandelbrot and Wolruf, managed to destroy Aranimas’s ship at great cost to their own vessels. They had only one option left to them with Derec growing weaker: use the Key to jump back to Robot City.

They emerged from the Compass Tower into Avery’s vacant office, intending to force the doctor into helping Derec. To find him, Wolruf and Mandelbrot went into the city, while Derec and Ariel began searching the tunnels underneath the tower.

Mandelbrot and Wolruf found that the robots were all following the orders of what they called the Migration Program. They were leaving the first Robot City and seeking new worlds on which to build. And when they returned to Compass Tower, they found that Hunter-Seeker robots were searching for Derec and Ariel, who had fled.

Above the planet, a small spacecraft arrived, carrying Jeff Leong. Back to normal, he was returning to rescue the others. Meeting with Derec and company, he was determined to help them find Dr. Avery.

It was actually Dr. Avery who found them, the Hunter-Seeker robots capturing the company one by one. The Doctor revealed that Derec was actually David Avery, Dr. Avery’s son, and that the chemfets in his body would one day allow him to control every Avery robot in existence. Derec would become Robot City.

But Avery had believed Derec would be a willing partner in his plans. He was very wrong in that. Derec used his new control of the city to free his companions; Dr. Avery triggered a Key to Perihelion before he could be captured. He fled into the void.

Derec and the others gave no thought to pursuit. At last, they were safe and free to leave.

It seemed reward enough…