Baby Baa-chan

Amika is a elementary school student who dreams of becoming an idol. Her grandmother is a harsh yet wealthy woman who lives on a remote island that she owns. When her grandmother passed away, Amika's life begins to appear subtle changes. Not long after the passing of her grandmother, Amika's mother gave birth to a baby girl. Ironically, Amika's little sister looks and behaves exactly like her grandmother.
(Source: Anime News Network)