Gaster's Exempla (1924), No. 140, tells the tale in a handful of sentences — which is precisely its horror.
The two sons of Rabbi Reuben ben Astribulos lived in Tiberias. One day word reached them — perhaps a dream, perhaps a hint from a teacher — that the Angel of Death had been assigned to collect them soon. They panicked. They packed quickly. They fled south, far from Tiberias, into a region where the angel, they thought, had no business.
They arrived in the South and dismounted in the town square. The Angel of Death was already standing there, waiting. He did not scold them. He did not chase them. "I was told I would find you here," he said, and the errand was finished.
The motif echoes an older tale from the Talmud: two men tried to outrun death by leaving Samarkand for Luz, only to find death already sitting in Luz with their names on its schedule. The message is not that running is foolish. The message is that the map of a person's life is drawn not in roads but in days, and no distance you can cover with your feet will get you off the page Heaven wrote.
The only direction you can run that death cannot follow is inward — toward Torah, toward teshuvah, toward the kind of living that makes the appointed day less a cutoff than a handoff.