Year zero
ISO 8601:2004 (and previously ISO 8601:2000, but not ISO 8601:1988) explicitly uses astronomical year numbering in its date reference systems. Because it also specifies the use of the proleptic Gregorian calendar for all years before 1582, some readers incorrectly assume that a year zero is also included in that proleptic calendar, but it is not used with the BC/AD era. The "basic" format for year 0 is the four-digit form 0000, which equals the historical year 1 BC. Several "expanded" formats are possible: −0000 and +0000, as well as five- and six-digit versions. Earlier years are also negative four-, five- or six-digit years, which have an absolute value one less than the equivalent BC year, hence -0001 = 2 BC. Because only ISO 646 (7-bit ASCII) characters are allowed by ISO 8601, the minus sign is represented by a hyphen-minus.
Red Eyes
The year 2001 became the new first year of the new era, known as 1 GU (first year of the Great Unification's calendar), however in 50 GU (2050 AD) an unknown power is able to hack in the SDI system, forcing the system in SafeMode, making the system unable to process order from the DUPE command centre (except its original mission to intercept any launched ICBMs and missiles). As result of losing its deterrence system, the other countries of the planet launch a full-scale attack against the DUPE forces, beginning the "20 years war" (World War III) that ended de facto in 70 GU (2070 AD) with no winner and the death of half the population of the planet, while all main actors of the war eventually dissolved and ceased to exist following the mutual destruction.