"We're in a hell of a jam, Brek," the Councillor said. "If Sagginer isn't stopped, he'll change history. The situation's desperate." Time Patrolman Brek Halliday nodded in agreement. It was a tense situation. Time travel, he knew, was possible only so long as the traveller into the past did nothing that would change history significantly; the time-stream itself would straighten out little changes in the past so that overall history would remain the same. But a big change was something else again