On November 17, 1968, the Oakland Raiders score two touchdowns in nine seconds to beat the New York Jets—and no one sees it, because they’re watching the movie Heidi instead. With just 65 seconds left to play, NBC switched off the game in favor of its previously scheduled programming, a made-for-TV version of the children’s story about a young girl and her grandfather in the Alps. Viewers were outraged, and they complained so vociferously that network execs learned a lesson they’ll never forget: “Whatever you do,” one said, “you better not leave an NFL football game.”

The game between the Jets and the Raiders was already shaping up to be a classic: It featured two of the league’s best teams and 10 future Hall of Fame players. By the game’s last minute the two teams had traded the lead eight times. The game’s intensity translated into an unusual number of penalties and timeouts, which meant that it was running a bit long.

With a little more than a minute left to play, the Jets kicked a 26-yard field goal that gave them a 32-29 lead. After the New York kickoff, the Raiders returned the ball to their own 23-yard line. What happened after that will go down in football history: Raiders quarterback Daryle Lamonica threw a 20-yard pass to halfback Charlie Smith; a facemask penalty moved the ball to the Jets’ 43; and on the next play, Lamonica passed again to Smith, who ran it all the way for a touchdown. The Raiders took the lead, 32-36. Then the Jets fumbled the kickoff, and Oakland’s Preston Ridlehuber managed to grab the ball and run it two yards for another touchdown. Oakland had scored twice in nine seconds, and the game was over: They’d won 43-32.

But nobody outside the Oakland Coliseum actually saw any of this, because NBC went to commercial right after the Jets’ kickoff and never came back. Instead, they did what they’d been planning to do for weeks: At 7 PM, they began to broadcast a brand-new version of Heidi, a film they were sure would win them high ratings during November sweeps. Before the game began, network execs had talked about what they’d do if the game ran over its scheduled time, and they decided to go ahead with the movie no matter what. So, that’s what NBC programmer Dick Cline did. “I waited and waited,” he said later, “and I heard nothing. We came up to that magic hour and I thought, ‘Well, I haven’t been given any counter-order so I’ve got to do what we agreed to do.’”

NBC execs had actually changed their minds, and were trying to get in touch with Cline to tell him to leave the game on until it was over. But all the telephone lines were busy: Thousands of people were calling the network to urge programmers to air Heidi as scheduled, and thousands more were calling to demand that the football game stay on the air. Football fans grew even more livid when NBC printed the results of the game at the bottom of the screen 20 minutes after the game ended. So many irate fans called NBC that the network’s switchboard blew. Undeterred, people started calling the telephone company, the New York Times and the NYPD, whose emergency lines they clogged for hours.

Shortly after the Heidi debacle, the NFL inserted a clause into its TV contracts that guaranteed that all games would be broadcast completely in their home markets. For its part, NBC installed a new phone–the “Heidi Phone”–in the control room that had its own exchange and switchboard. Such a disaster, the network assured its viewers, would never be allowed to happen again.