Conversation so far:
what is the movie it's a wonderful life about
It's a Wonderful Life is about angel sent from Heaven to help a desperately frustrated businessman by showing him what life would have been like if he had never existed.
who directed it's a wonderful life
It's a Wonderful Life was produced and directed by Frank Capra

Question: what is the movie based on
Self-contained rewrite: what is the movie it's a wonderful life based on