Sumire

Sumire (real name unknown) is a very cute and nice girl who has lost her memory of the past 3 years due to some mysterious event that had happened. She is found by the the twins and is taken to the boys dorm where the Idols live. The first time they meet her they think that she's probably just another crazed fan pretending to have lost her memory to get close to them. But soon after she faints and is taken to th hospital where it's revealed that she is truly suffering from partial amnesia. So the Idols take her in and start caring for her since she has no other place to go to. As the story progresses she falls in love with Yamato (one of the Idols), who also later on returns her feelings. He is also the one who gave her the name Sumire which is a name of a flower and means "Hope". (Source: K0K05)