|“|| I thought we were alone in the universe?!!|
- GDI Soldier when the Scrin arrived
It was not until later that it was revealed that Kane had knowingly provoked GDI into using the Ion Cannon to detonate the bomb, which he knew would attract the attention of a Tiberium-based extraterrestrial race, known as the Scrin. They took this as a sign of advanced Tiberium infestation on Earth, and arrived in force even in the battle against GDI in parts of Europe, Asia and Australia while NOD after their headquarters in Sarajevo was destroyed by the same GDI superweapon battled the aliens in Australia, Europe, Africa and Asia.
The InvasionShortly after the Siege of Temple Prime, GDI deep-space satellites picked up motion on the edge of the solar system.
This turned out to be a fleet of non-terrestrial ships, headed for Earth at "near-relativistic" speeds.
Director Redmond Boyle of GDI ordered an Ion Cannon strike against the invaders with the entire network of cannons all over Blue Zones like the British Isles.
Scrin forces began constructing massive Threshold towers in the world's Red Zones like China for example, but still unclear purposes.
At the same time the Scrin began attacking major population centres - GDI and Nod alike - with a ferocity unmatched before or since.
Shock troopers stormed major Blue Zone cities like London. Kane, meanwhile, went underground, although he continued to issue orders to his most trusted associates, including LEGION and Alexa Kovacs, while plotting his next move. Meanwhile in Australia, Kilian Qatar assumed leadership of the Brotherhood after GDI reports that Kane is dead in Sarajevo.
First Battle of Munich - The Scrin have to use their commando to ultimately allow reinforcements to arrive. They are then to be used to destroy the GDI base in order to secure vital data for Threshold and Relay Node construction. (TW)
Second Battle of Munich - GDI has to escort and evacuate key scientists while defending themselves from the Scrin onslaught. (TW)
Outback - The Nod forces in Australia must take at least one GDI nuclear truck to an LZ during the Scrin attack. (TW)
Liberation of Stuttgart - GDI commando Lieutenant Fullerton must rescue GDI forces pinned down by Scrin forces. Amongst those forces are engineers which are to be used to restore the GDI base to operational status and to capture the Scrin Drone platform. (TW)
Battle of Sydney (Two Part Mission) - After an unholy argument over GDI and Nod working together against the aliens, Nod must destroy Scrin forces at the Sydney city wall whilst capturing the nuclear codes in the first part and protect the evacuation Ox transports until Kane orders the destruction of GDI's base in Downtown Sydney during the second part. (TW)
Liberation of Cologne - GDI must scout out and destroy Scrin forces, the Drone platform in particular, occupying a former Blue Zone. (TW)
Battle of Berne - GDI forces must end the Alien invasion of Europe by attacking the Scrin's main headquarters in Berne, Switzerland. GDI command insisted there be no survivors; revenge on the Aliens for attacking major cities in both Germany and the United Kingdom. (TW)
Second Battle of Croatia - The Scrin must destroy both Nod and GDI bases to capture a Nod building containing the answers to the premature liquid tiberium explosion. (TW)
Rome - GDI has to push through Scrin and Nod defences to destroy a major Threshold tower, the one closest to completion at that time. (TW)
Operation Stiletto - Nod must turn GDI and Alien weaponry against them to spare Nod troops for the defence of Kane's Tower. (TW)
Kane's Tower - Nod has to defend the last remaining tower known as Threshold 19 from GDI attacks. The destruction of all of GDI in this region is essential. (TW)
Threshold 19 - The Scrin must defend the last Threshold tower from GDI forces until completion and then guide the Mothership to the Tower. Destroying the GDI base is optional. (TW)
In Europe, the Scrin destroyed many major blue zone cities in GDI territory - London and Berne being just two of the most publicised, horrifying cases for the Earth's factions. At the same time, New Eden in Germany, the crowning achievement of GDI's Tiberium eradication plan, and a vital research hub, fell to the invaders. Though Munich was destroyed in both battles, the GDI Commander managed to guide the researchers to safety. Here GDI discovered that Sonic emitters, designed for the destruction of Tiberium, had a powerful effect on the Scrin, damaging them severely. Exploiting this weakness, GDI set to work retaking the destroyed region of Stuttgart with a GDI commando, Lieutenant Fullerton rallying his pinned down GDI troops to victory in the city. Later GDI victories followed at Cologne and Berne.
The Scrin also operated elsewhere in Europe, most notably in Croatia, where they come into conflict with both GDI and Nod forces.
Although Kane saw the Scrin as "visitors", not "invaders", LEGION was nevertheless forced to deal with the Traveler-59 subfaction which arrived and started to mind control the Nod-friendly population in the African Red Zone. When LEGION started to destroy their Drone Ships the Scrin brought in an Eradicator Hexapod as its reinforcements. LEGION countered it by deploying Nod's own Redeemer to take out this alien building.
In China, both GDI and Nod factions fighting over the Tacitus were ambushed by a division of the Scrin's dreaded Reaper-17 subfaction. Meteors laden with Tiberium rained down on the city followed by ground troops of GDI and NOD.
With Kane apparently dead in Sarajevo, Kilian Qatar becomes the de facto leader of Nod although she was suspected of starting the rebellion at Temple Prime. She recalled all Nod personnel to fight in the last stand in Australia, vowing to retake the world one continent at a time. While a Nod team sent by General Qatar was busy hijacking GDI nuclear weapons in transit from the Outback to the main base in Sydney, they were ambushed by the Scrin invasion force which attacked GDI and Nod indiscriminately after Ajay, the Nod Intelligence officer contacted the commander about the bad news after capturing the last GDI convoy. Nevertheless, the nuclear weapons were secured.
Kilian Qatar saw that the most logical option was to ally with GDI against this new terrifying enemy, and aided them in the defence of Sydney (while taking the opportunity to steal the nuclear launch codes from GDI). Despite the GDI-Nod Alliance, the Scrin broke through the city's defences and a hasty evacuation of Sydney was ordered. While GDI struggled to hold their ground, the Nod forces received an order from the recently-resurfaced Kane alive to destroy the GDI forces. The GDI defenders were obliterated with a nuclear missile. Afterwards, Kane reasserted his leadership of Nod at the Battle of Ayers Rock.
With the alien assaults repulsed, both GDI and Nod are now ready to venture into the Red Zones. The ensuing Italian Campaign culminated in the Battle for Kane's Tower and the Battle for Ground Zero, with Kane capturing the only completed Threshold and GDI destroying the Relay Node, depriving the alien units of their Tiberium radiation, killing them. Foreman 371, however, had escaped through the Threshold to the Ichor Hub.