Tonight in the darkness, an ancient ritual will begin, as it has every night for almost a thousand years. With bare feet and in complete silence, the Poor Clare sisters of Roswell, N.M., will rise from their beds, don their cowls and begin to pray for your soul.
Each night, these nuns allow themselves no more than three hours of sleep. Their calling is an extreme one: to stay inside the walls of their convent and spend their days and nights in prayer and silent contemplation.
They are part of a small number of nuns in the United States who are cloistered, meaning they do not interact with the outside world except by necessity.
There are only 1,412 cloistered nuns out of 66,608 sisters in the United States. They take four final vows: chastity, poverty, enclosure and obedience, and they follow a rule of silence.
For their enitre lives, their time will be divided between constant prayer and the work of the convent. Most do not read novels, see movies, or play sports. They do not hug one another and keep all physical contact to a minimum. Most of them rarely, if ever, see their families.
These are not the nuns we are familiar with, called apostolic nuns, who teach or minister to the poor. These sisters spend their days in silence and isolation, giving up not only the outside world but often whatever gives them pleasure, however small.
They have sacrificed everything worldly to focus entirely, and without distraction, on praying to God.
At the Poor Clares convent, the ferocity of self-denial the nuns practice is impressive. Not a word in the halls, not a whisper at breakfast, which is eaten standing up, in remembrance of the Israelites on their way to the Promised Land.
The Poor Clares order began in the Middle Ages as a movement against the increasing worldliness and laxity of the church. Every crumb of the sisters' food, the two small pieces of bread and cup of coffee they have for breakfast, for example, must be consumed. Work is always done in constant, quiet prayer whether, they are sweeping floors or making a simple lunch.
There is silence in the garden and silence in the halls. If they must communicate, sign language is used, and the sisters have hand signals for everything from "time" to "temptation."
Not everyone is cut out for the kind of sacrifice this life demands. Those who are, Sister Terrasita explained, are "called to be mothers of all souls in the world."
At night, they sleep, though they wake up in the middle of the night to continue their prayers. The late Rev. Mother Mary Frances said that sin loves the color of night.
"More people die in the night than during the day, so we're very much conscious at this midnight hour. It's dark and quiet and people are dying. They're going before the judgment of God. And so it is wonderful that people that we will meet only in eternity will meet us, that we are praying for them."
Young women are still called to that prayer, unbroken since the Middle Ages.
The order of the Cistercian Abbey of Mount St. Mary's in Wrentham, Mass., like Poor Clares, was also started in the Middle Ages.
"2020" was allowed into the convent on a weekend, when seven young women were deciding if they were going to give up the material world and choose the contemplative life of the sisters at Mount St. Mary's Abbey.
What is it about this austere life that would induce these seven women -- students, professionals, who have had relationships with men -- to give up family, career or home ownership?
Christine Curran, 28, once worked as an editor for a Washington journal. "I guess it's just a feeling of wanting more. Careers sound wonderful, [but] the more I think about things like that, it still doesn't capture enough of that feeling inside me. It's like you want to give yourself in a deeper way."
Katherine Whetham, 24, a theology grad student at Boston College said, "Honestly, there's no other choice for me. That's what I feel. There's nothing else that I know. So even though this looks very difficult and hard or maybe impossible or a failure, it is worth the risk. I'm certain. I hope God is certain."
But Whetham is also very much like other young women her age. "Their habit is really awesome. I like black and white. It's simple. That's the cool thing. I like simple clothing. I'm pretty monastic already."
The call to monastic life must be strong to lure women like these away from the pleasures of the world -- from new clothing and music, to sex, families and children. But will they forsake their lives to go behind these walls?
To find out, watch "2020" Friday at 10 p.m., EDT, as Diane Sawyer explores life behind the walls of a cloistered convent.