On September 11, 2001 the world changed. The World Trade Center collapsed into dust, one side of the Pentagon crumpled, and a fourth hi-jacked airline crashed into a field in Pennsylvania before it reached its unknown target. And for the first time in history, American airspace closed. Immediately following the terrorist attack, 252 international flights carrying 44,000 dazed and frightened passengers were suddenly ground in Canada. Many of these passengers had landed in places they had never heard of. Every hotel room was soon accounted for, but within hours, Canadian ingenuity turned stadiums, churches, service clubs and schools into emergency shelters. Using footage from those harrowing days, personal videos, moving interviews, and recent reunions, A DIARY BETWEEN FRIENDS follows individual Americans and Canadians as they give support and friendship to each other.