St. Gregory the Great, in his Dialogues, tells us that she was a nun and leader of a community for women at Plombariola about five miles from St Benedict's abbey at Monte Cassino. We do not know what rule this community followed, although it seems most likely it was the Rule of St. Benedict.
Scholastica was dedicated to God from a young age (some tellings of her story indicate that she preceded Benedict in godliness, and he came to holiness after she did, and in her wake). The most commonly told story about her is that she would, once a year, go and visit her brother at his abbey, and they would spend the day worshiping together and discussing sacred texts and issues.
At the end of the day, they had supper and continued their conversation. When Benedict indicated it was time for him to leave, she protested, and begged him to stay with her for the evening so they could continue their discussions. He refused, insisting that he needed to return to his cell. At that point, Scholastica closed her hands in prayer, and after a moment, a wild storm started outside of the guest house in which they were housed. Benedict asked, "What have you done?", to which she replied, "I asked you and you would not listen; so I asked my God and he did listen. So now go off, if you can, leave me and return to your monastery."
Benedict was unable to return to his monastery, and they spent the night in discussion. According to St. Gregory's Dialogues, three days later, from his cell, he saw his sister's soul leaving the earth and ascending to heaven in the form of a shining white dove.