They took the body of Park Lacoch and stripped away his mind, transferring the mind of a top Confederacy operator to his brain. then they stuck him aboard a spaceship and exiled him to Charon, one of the Worlds of the Warden Diamond, from which no man could ever return. A mysterious organism on those worlds infected everything making life away from them impossible afterwards.
Charon was a hell-world in literal fact. It was too near its sun, making life all but unbearable in its hot, stormy atmosphere. Strange beasts roamed its jungles - and stranger still, the group known as the Witchcraft plotted with the Lord in exile to take over the planet.
There Witchcraft was real - for on Charon, magic worked! The Warder organism could be made to perform almost any feat under the control of a skilled witch or sorcerer - as Park Lacoch discovered when he was transformed into a changeling - a half-beast half man, with the beast rapidly gaining ascendancy.
After that, his assignment really became difficult
THE MAN WITH FIVE MINDS
He was the toughest, most cunning of all the Confederacy's assassin-operatives. When the impossible had to be done to protect the security of civilization, he was the one called. then his mind was wiped, and he was given a luxurious vacation until brought back for the next job.
Not this time, however! This time they needed to transfer his mind into the brains of four criminals sentenced to the mysterious Warden worlds, the Confederacy's dumping ground for dangerous criminals. Return from the Warden worlds was impossible because of a strange organism that invaded every living thing - and most other objects as well.
Only his mind could insure the assassination of the Four Lords of the Diamonds, the rulers of those world,s who were in league with aliens who threatened the existence of the Confederacy.
Now the four criminals were gone, and their activities were being beamed back to him - each in a sense reflecting the assassin's actions, each criminal somehow the assassin himself. and they were not doing what he knew they should do.
To his horror, he found his own mind changing as he lived their lives with them. The Confederacy depended on him - but he was rapidly losing himself! [Or maybe finding himself for the first time in a very very long time]