Rikka's Planet was one that was settled by Honored Matres during the Scattering, and had a world generated no-field shielding the globe from outside eyes.
It was a world that the final ghola of Duncan Idaho folded space and took the no-ship the Ithaca to, when fleeing from the Enemy during the advent of Kralizec. Sheeana and Garimi took a landing party down to the planet to investigate why there were no human life signs at all on the world.
The planet had evidence of a very advanced human civilization that was governed in typical Matre fashion, with ornate buildings with gaudy decor'. But evidence showed, that the civilization had come to a complete, abrupt halt, hundreds of years before the Ithaca's arrival. Dense vegetative overgrowth covered much of the plazcrete buildings, and most electrical and heating grids had failed.
When Sheeana's party reached what appeared to be a Matre courthouse and detention center, Sheeana activated a holo-projection of the last recorded trial. The recording showed a trial of a Matre leader and military commander, Rikka; being judged before Matre officials.
Rikka testified that she had boils on her arm from a great plague; which Other Memory in Sheeana identified as the Omnius Scourge; and that an Enemy with "many faces" had given it to her and her fellow fighters. Because Rikka had broken quarantine and brought the Scourge to the planet, she was being accused and charged, and was subsequently; in the holo; found guilty. The tribunal in the recording pronounced that her punishment was the Long Death.
After the holo was done playing, Garimi remarked that the Scourge was 100% deadly, but only lasted three to four weeks in general, and then was rendered itself powerless.
After Sheeana and Duncan learned of the fate of the occupants of the planet, and the fact that its' location was already known to the Enemy, Idaho decided to fold space again, and took the Ithaca to another location.
The planet's name was never found out by the crew, and therefore has come to be know as "Rikka's Planet".