Shortly after these events, Mamoru leaves for the United States to study abroad while Usagi and her friends enter high school. Chibiusa also returns to her own time. A group of enemies called the Sailor Animamates — led by Sailor Galaxia — begin targeting humans for their Star Seeds (which serve as a human's life force). Usagi is also aided by the Sailor Starlights — Kou Seiya (Sailor Star Fighter), Kou Taiki (Sailor Star Maker), and Kou Yaten (Sailor Star Healer) — who disguise themselves as an idol group named the Three Lights. The Starlights are searching for their ruler, Princess Kakyuu. A young girl — nicknamed Chibi Chibi because of her limited vocabulary that usually involves the word "chibi" — also appears and begins living with Usagi.