Sometimes it's really hard for me to understand what does a word of "beyond" mean.
In the movie Arrival the character of Amy Addams says:
I'm not so sure I believe in beginnings and endings. There are days
that define your story beyond your life. Like the day they arrived.
The only guess I have is the second sentence means something like: There are days that affect your story even though you life hasn't began yet.
Best Answer
Google Dictionary
I'd say "days that define your story beyond your life", means, outside of your life as if it could be viewed in its entirety from outside and examined. This examination would help you to understand and define your life.