To discover the secret behind a terrifying riddle presented to him, Buck subjects himself to a mind probe in an attempt to find out who is responsible for the mysterious objects being transported into the Defense Directorate's building.

Buck is haunted by the appearance of a young woman who bears a striking resemblance to Jennifer, a woman who Buck left behind when he was propelled into the 25th Century. He follows her, finds out her name is Leila Markeson, and soon discovers that she was made to look like Jennifer in order to lure Buck into a trap set by an alien who wants Buck to stop a space freighter from delivering weapons to a planet his people hope to conquer. Buck gets Wilma to detonate a warhead to deceive the aliens into thinking the shipment is destroyed. Buck defeats the enemy, but loses Leila, and his lost love again, as she tearfully dies in his arms.

Buck, Wilma, and Hawk explore a strange planet and come across the wreckage of a spacecraft and its lone survivor. He is taken back to the Searcher by Wilma, while Buck and Hawk continue to explore. After some unexplained happenings on the planet, they return to the Searcher, where they find that everyone has undergone personality changes -- becoming the opposite of their real selves. Buck soon learns that he can not even trust Wilma and Hawk to help him solve the mystery of what has happened.