In this flashback from "I am Legend", it represents how a virus spread and caused the people in the city to get sick and mutate wiping out the human population.
In this flashback in "Freedom writers", it shows how Eva became who she was because her father got arrested and she ended up getting into the gang that her father was in.
In this flashback from "Matilda", it shows how she was always an odd advanced kid who didnt really connect with her family.
In the present time in "I am Legend", Will Smith ends up being the only healthy person in his city and is accompanied by his dog because everyone else got infected. Will Smith is trying to find a cure.
In the present time, Eva ends up testifying against her current boyfriend which goes against her gangs rules and ends up betraying her father and her whole family, plus her gang to do what was right.
In the present, Matilda develops her powers and gets adopted by her teacher and finally feels like she is loved and belongs.