The US' massive prison population is getting older. Long sentences that were handed out decades ago are catching up with the American justice system. Prisons across the country are dedicating entire units just to house the elderly. During difficult economic times, the issue has hit a crisis point. Estimates are that locking up an older inmate costs three times as much as a younger one. How are prisons dealing with this issue? Who are the prisoners that are turning gray behind bars? Josh Rushing gains exclusive and unprecedented access to jails and prisons across the country to tell the story.