London, 1969. The last days of the manual telephone exchange. While the new automated switchboards are being installed across the nation, an operator resents connecting phone calls that are ending the careers of her colleagues. Never shy of a prank, Susan commits herself to take it further, using her skills of eavesdropping, rumour-spreading, and call-misdirection to save the present from the future. The upgrades arrive in Birmingham and she successfully diverts and disrupts them; yet within days the threat starts to close in on London itself.
Unable to match the efficiency of the system, Susan must contend for the human side of the technological sector. She faces an industry that prefers the superfast dreams of its visionaries, promising instant connectivity and the removal of human error. Susan refuses to leave, in part to complete her employment, and in part to wait for the impossible return of a precious fellow operator.