Insanity - The Loud House
Luna Loud is the rockstar of her family, always playing the guitar and songs for her own enjoyment and also for her siblings', but one day, she suddenly stops. It isn't noticed at first, but over time, everyone has noticed Luna's lack of enjoying herself.
Things also get worse, and one day, Luna suddenly goes missing, and this takes a toll on everyone, Luan especially.
Luan always had gotten along with Luna the best and they always cheered each other up when one of them was upset. Luan gets so lost without Luna, she doesn't know what to do without her, and then, Luan started acting strange.
Her behavior was beyond strange, actually, it was more crazy and unnatural, something beyond human. Then, she also disappeared without a trace, just like Luna.
Although one day, everyone else in the family discovers what actually happened to Luna and Luan, and it shocks the whole entire family.