Thousands of students didn't have computers or reliable WiFi. Many were falling behind. So as spring gave way to summer, Mayor Muriel E. Bowser (D) was determined to open schools again.

By mid-July, she had a plan. But it depended on cooperation of the teachers, and their union responded with protests.

Hours before the mayor was to make an announcement, she said she needed more time.

The city spent the next five months trying to bring students and teachers back to classrooms. A combination of mismanagement by the mayor and her aides and intransigence from the District's teachers union combined to thwart every move, according to interviews with city officials, union leaders, educators and activists. The city kept changing its plan, and the union kept changing its demands. A lack of trust on both sides fueled failure at every turn.