Year zero
Year zero does not exist in the anno Domini system usually used to number years in the Gregorian calendar and in its predecessor, the Julian calendar. In this system, the year is followed by . However, there is a year zero in astronomical year numbering (where it coincides with the Julian year ) and in ISO 8601:2004 (where it coincides with the Gregorian year ) as well as in all Buddhist and Hindu calendars.
Panic in Year Zero!
After a harrowing journey, the Baldwins reach their destination and find shelter in a cave, while they wait for order to be restored. On their portable radio they listen to war news and learn what is left of the United Nations has declared this to be "Year Zero". Harry and Rick find that Johnson and his wife are their neighbors, but not for long; they are killed by the thugs.