"People assume that time is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint - it's more like a big ball of wibbly wobbly... time-y wimey... stuff. "Doctor Who Blink, 2007T
his is how it could have been. Realities crash and new histories are made. In one world, people go about their life, in other realities the same people lay dead. In this world, things have happened for the good and for the bad, and the result is a changed world.
In 1981 Lord Voldemort arrived at Godrics Hollow to kill the infant Harry Potter, though Lily and James fell, young Harry survived and Voldemort was destroyed, for now.
In the events that followed, Peter Pettigrew was accused of betraying the Potters, but before anyone could capture him, he transformed into his rat form and escaped.
Sirius Black was a free man where in a different timeframe he would have been sentenced to Azkaban.
So the young Harry grew up with his godfather, and now that Harry Potter is coming to Hogwarts to begin his education in the magical arts. This world is a changed world, but what else has changed?