Love Live! School Idol Project 2nd Season

Synopsis

After an agonizing wait for the results, the girls are delighted to discover that μ's, along with A-Rise, has qualified the first preliminary round. As the girls strive to practice hard for the next round, Nico seems to be preoccupied by something, so the others decide to follow her, though she ends up spotting them and escapes. While wondering what Nico is up to, they end up meeting her younger sister, Kokoro, who, along with her siblings Kotaro and Kokoa, has been led to believe that Nico is the star of μ's and the others are merely her backup dancers. After finally being pinned down by the understandably bemused girls, Nico explains she has been skipping practice to look after her siblings while their parents are away, stating that she has been telling them she was a super idol from the beginning. Nozomi believes she has kept this front up even after her attempt at being an idol during her first year fell apart, as she didn't want to destroy their vision of her. Upon hearing about this, the girls arrange for Nico to give a special performance for her siblings, claiming it to be her last performance as a 'solo idol' before joining her fellow idols as equals in μ's.

(Source: Wikipedia)