This is based on the Kurt Vonnegut Junior short story 2BR02B.
In a future society, a paradise has risen from the ashes of the previous destruction. Nature has healed, there is peace, and there is prosperity kept alive by maintaining a zero population growth. People can live to be two hundred or more years old, providing the population does not change. If, however, someone in a family has a child, someone else must die to keep the ledger balanced.
Mordred Meeks has a granddaughter who just had a baby daughter. He has volunteered to die for her. It is his honor to do so for his family. Plus, he is awarded the title of volunteer of the week and in the running for volunteer of the year because at 93, he is one of the youngest volunteers Preserving Paradis has had. He gladly goes to his death while his granddaughter puts his token of affection on her infant's ankle. The token is a bracelet that living people wear so that their lives can be kept track of. It stays on them until they die.
Hansom Chiles' wife is about to have a baby. Liza Little, his maternal great-grandmother, has been chosen to be the volunteer, but there's a problem. Mrs. Chiles has triplets, so they are two short. Liza who doesn't particularly want to be a volunteer must come up with a plan to save herself and her family.