Some may think the Half-Life events are just fiction. But as we've learned in the series, never let gordon push a button that will turn a huge machine on. We know it won't work as we expect. This time, Dr. Freeman will join the CERN team at the Large Hadron Collider, the biggest experience in the world researching deep inside matter, and what can come out from it. This time, the enemy is the unknown. After the disaster, physics around the facility has been intensely improved and this may help you through your journey or not. Like in Nevada, the marines will try to control the situation, but years have passed and they have new technology. Help the remaining scientists to find the Higgs-boson, a primitive particle capable of altering mass from stuff and stabilize the LHC before it colapses into a small blackhole that will suck Earth and everything near it.