"Shall we play a game?"
The computer stages a massive Soviet first strike with hundreds of missiles, submarines, and bombers. Believing the attack to be genuine, NORAD prepares to retaliate. Falken, David, and Jennifer convince military officials to cancel the second strike and ride out the attack. WOPR tries to launch the missiles itself, however, using a brute-force attack to obtain the launch code. Without humans in the control centers as a safeguard, the computer will trigger a mass launch.All attempts to log in and order WOPR to cancel the countdown fail. Disconnecting the computer is discussed and dismissed, as a failsafe will launch all weapons if the computer is disabled.
Falken and David direct the computer to play tic-tac-toe against itself. This results in a long string of draws, forcing the computer to learn the concept of futility and no-win scenarios. WOPR obtains the missile code, but before launching, it cycles through all the nuclear war scenarios it has devised, finding they, too, all result in stalemates. Having discovered the concept of mutual assured destruction ("WINNER: NONE"), the computer tells Falken that it has concluded that nuclear war is "a strange game" in which "the only winning move is not to play." WOPR relinquishes control of NORAD and the missiles and offers to play "a nice game of chess."