In the final episode of the series the decision is made by the galactic council that mankind is irredeemable and that the Earth is to be destroyed. Although Pukko is in favor of this as much as ever, Bokko puts off the order as long as possible, and eventually decides to disobey the council's decision. However, prior to Bokko's decision to disobey her orders, Shinichi is appalled at the likelihood that his friends would obey the order and runs to Koichi to ask Phoenix to intervene.

Although dozens of Phoenix agents fight the Amazing 3 in their saucer, they are unable to destroy it, and Shinichi appeals to Bokko, Nokko, and Pukko to take him back to their home planet to plead Earth's case. During the trip Bokko, Nokko, and Pukko revert to their humanoid forms for the first time, much to the surprise of Shinichi, who had never seen their true appearances before (perhaps not clearly, anyway - he had also seen them through the window of their saucer in the first episode, though it's suggested in the episode that he could only see their silhouettes).

Shinichi is particularly surprised by Bokko's beauty in her actual form. A3 are presented to the galactic council on charges of disobeying orders. Shinichi is given a chance to plead Earth's case and the council offers him the opportunity to stay on their planet with all the rights and privileges of other citizens. Shinichi becomes angry and attacks a guard, thus proving mankind's inherently violent nature to many there.

The order is given to wipe out Shinichi's memories, but before this can be done Bokko pleads for him to be released, and for the Earth to be given more time to develop. The council eventually decides to return A3 to the Earth and re-examine the matter when Shinichi reaches adulthood.

Upon their return to Earth Pukko is ashamed of his attitude toward humans before that point, Shinichi is reunited with Koichi, and Bokko is transformed by Nokko and Pukko into an Earth girl so she'll have a chance to be with Shinichi as the human girl she really wants to be - for a short time, anyway. The closing shot of the series is of the now-human Bokko walking towards Shinichi's home to find him.