The Queen of the Moon, Dianna Soreil, is the inheritor of the Moonrace and has been ruling it for centuries using cryogenic techniques. Now that Earth has regenerated from its destruction during the Dark History, she believes her subjects should return to Earth. She lands a colonial force on Earth with the hope of settling in the sunbelt area of Americas. However, she fails to consider Terran resistance to migration and does not anticipate her more ambitious subjects turning against her while she's away. Events quickly spiral out of control. Dianna has lived for centuries and is tired of her unchanging life on the Moon. She is an intelligent and commanding leader but lacks the drive of her young double, Kihel Heim. When assuming Kihel's identity, she enjoys a simple life with Loran. She only returns to the Moon to correct her mistakes made during her hasty attempt at repatriation.
At the end of the series, Dianna permanently switches places with Kihel, and she and Loran lives out the rest of their days in a small cabin. Though she was shown in the end with a ring on her left hand, its debatable whether she and Loran really got married, since they sleep in separate rooms and Loran until the end kept addressing her formally as "Dianna–sama."