On Wednesday, the call came in from Chicago: President-elect Obama wanted to meet with Sen. Clinton, in private, the next day.
According to Democratic sources, Clinton disclosed the information to only three people and swore them to secrecy.
Clinton's team went to extreme lengths to keep the trip a secret. When Clinton arrived at La Guardia airport in New York for the Delta flight, she was the last person to board the plane. In Chicago, she was the first person to disembark.