I know what the movie was about!
Sunny realising she is out of ice cream. So on her way to by ice cream she finds herself with the destiny of fighting Dark Matter!
But she needs friends! She takes it down with the help of Mario, Sonic and Pikachu! She met them by travelling with the Calamity Box. But in the epic final she unfortunately loses her leg. Like how Hiccup lost his
(Satire)