In Gen 23:1, we read about Sarah's two lives.
וַיִּהְיוּ חַיֵּי שָׂרָה מֵאָה שָׁנָה וְעֶשְׂרִים שָׁנָה וְשֶׁבַע שָׁנִים שְׁנֵי חַיֵּי שָׂרָה
And Sarah's lives were 127 years long, Sarah's two lives.
We know from here that Sarah had two lives, each 127 years long. During which of her two lives do the Torah's stories occur (ie. the first or the second), and what do we know about Sarah's other 127-year life?