In 2016 Don Jr took an ill-fated meeting with a Russian lawyer in Trump Tower.
The meeting is a pivotal moment in the entire story of Trump and Russia and has since been called "treasonous" and "unpatriotic".
So is the meeting it a smoking gun or was it all just a waste of time?
This is the eighth episode of Russia, If You're Listening.
Each week, host Matt Bevan brings the story of a character involved in the investigation.
You can get in touch at russia@abc.net.au.
If You're Listening