AgroupofaliensarriveonEarthaspartofanadvanceinvasionforce.Theirmissionistokidnapasmallsampleofhumansandrunthemthroughaseriesofrigorousteststodetermineiftheywouldmakesuitableslaves.Harper,oneofthealienexperimenters,hasbecemefrustratedwithherplanet'sendlesscycleofconquestandexterminationandbeginstofeelsomesympathyforherhumancaptives.Whiletheprisonersseeaglimmerofhopeinthecompassionatealien,willitbeanyuseinstoppingtheenormousattackfleetjustafewdaysfromEarthaa