The nuclear power plant on the outskirts of town has had a…situation—a very serious situation. On the first day, the sirens went off. On the second day, news broadcasts said not to panic. On the third day, everyone panicked. On the fourth day, the area was told to take cover because the contamination had become airborne. On the fifth day, death and pestilence overtook a third of the population. On the sixth day, the area was restricted—no one comes in and no one leaves. So, what does that make today—it’s Doomsday.

You and your friends have taken shelter in an underground bunker that your crazy uncle built as soon as the nuclear power plant was erected. Maybe he wasn’t so crazy after all? You have been holed up for months with no end in sight. The air is still thick with chemicals. Your electronic system is failing. Something has damaged your air ducts. You have an hour of air remaining. You must adjust the pressure in the bunker and get the air stabilized or else your haven will be your tomb.