Robots were infiltrating the Federation. Someome was kidnapping the people and substituting indetectable synthetic imitations. Somewhere aliens were studying the Federation, using tectniques beyond human developments. The trail led back to Cereberus and the Lord who ruled that planet.
Cerberus, however, was one of the Warden worlds---and those Worlds were the untouchables of space. There a strange microscopic life-form invaded all matter, and anyone so infected died on leaving those Worlds. Men could go there, but never return.
But the Federation has its own techniques. They took a criminal namedd Qwin Ahang and steipped her mind of all memoiry and personality. Then they poured into that empty recepticle the full mind of the Federation's best opeative. They exiled her to the prision wourld Cerberus. The mission, Find the Lord who ruled, kill him. and take obver. Too bad there were things about Cerberus they could't know!
Somewhere from among the four human-settled worlds of the Warden Diamont, hostile aliens were spying on Earth. But no agent could be sent to investigate and report back. All trips to the Warden worlds were one-way. There, a microscopic symbiont invaded all life forms, after which life became impossible outside the Warden system. THe same organism destroyed any for of machinery, so no message could be beamed back by normal means.
Book two of four