Copyright statement, spoilers, and casting

Melissa wants two things badly in her life.
She wants to become a botanist.
But she really wants her sister Milly to get better.
The problem is Milly's hospital bills drain their mother's bank account.
So Melissa's mother forces all of Milly's caretaking to Melissa and her life takes a turn.
And just when Melissa needs her best friend for moral support, he disappears from her life.
In this case, Melissa has two choices.
She can either run away from her responsibilities...
Or she can rise to the occasion.