Agroupofdiverseindividualsaresuddenlytakenfromtheirhomesandflownviahelicoptertoafuturisticbombshelterinthedesert,one-thirdofamilebelowthesurfaceoftheEarth.There,theylearnthatanuclearholocaustistakingplaceandthatthey'vebeenchosenbycomputertosurviveintheshelterinordertocontinuethehumanrace.Theshelterisdesignedtoallowthepeopletoexistundergroundcomfortablyforyears,buttheyarefacedwithathreatnobodycouldhavepredictedacolonyofthousandsofbloodthirstyvampirebatsfindsawayintotheshelterandlaunchesaseriesofviciousattackswheretheyclaimthehumansonebyone.