An unfortunate event

"Not wanting to argue anymore, I said something I probably shouldn't have said: 'I dreamt of our old life...' "

Benjamin and Alexandria were ordinary teenagers until the day their parents passed away. With no relatives left, they were adopted by an abusive alcoholic who forced them to work for him. They thought that there was no hope of escaping when out of nowhere they found a mirror that allowed them to talk to their parallel universe selves.