Post-Combine invasion. Scientists on Earth detect interdimensional anomalies—strange creatures, portal storms, unexplained phenomena. World governments are briefed, via the UN. Dr. Kleiner makes a global broadcast, revealing the existential threat.

The UN is given real power to coordinate planetary defense. A new entity is formed—the United Earth. Every nation contributes military, scientific, and industrial resources. NATO, CSTO, BRICS, China, US, Russia, EU, Iran, Israel, North Korea—even historical enemies sign a Planetary Defense Pact. Arms races are redirected from competing against each other to preparing for the Combine invasion.