What's behind the curtain?
Hilary seemed to see a pair of dark gray eyes...
Using the curtain as a bridge, connecting twenty years of time
It brings Sirius Black and Hilary Potter together in Hogwarts before the storm
In short, it tells the sweet story of Sirius Black falling through the curtain and returning to his student days; and Hilary Potter accidentally coming to the life of her parents and godfather in order to recall her godfather's body.