S1·E6 Gamma Ray Burst

The most powerful blast of cosmic radiation in the Universe is just seconds from slamming into Planet Earth. When a gamma ray burst from two colliding stars hits the atmosphere, the deadly radiation delivers agonizing death and immediately wipes out half the planet. On the other side of the Earth, the Americas face a slower death as ultraviolet radiation and starvation threaten to send the human race into extinction. How will the last remaining humans survive?