Six years after the conclusion of the One Year War (UC0086~0087). A girl who lost not only her parents, but her own memory by a colony dropping thanks to the Zeon, is recruited into a Newtype research institute (the Murasame Labs). After aimlessly wandering, she becomes test subject No. 004 (aka "Four"). Here she is trained to become a strengthened human with two other subjects (No. 005 Jill Ratokie and No. 006 Amari Garfield). The intense training killed many people, and yet through it all Four and Jill comfort each other. On the other side of the spectrum, at the Augusta Laboratory, Dr. Murasame learns of their plans to create another artificial newtype: Rosamia Badam. Murasame studies Rosamia's memory. It appears that the fear of a colony dropping amplified the newtype potential. In order to do this, Amari and Jill would be used.

(Source: zeonic-republic.net)