WhiledrivingthroughthedesertwithhiswifeCarolMarvintoamilitarybasetosendtheeleventhrockettotheorbitofEarthforhelpingtheexplorationoftheouterspaceintheOperationSkyHook,Dr.RussellA.MarvinandCarolseeaflyingsaucerandaccidentallyrecordsamessageintheirtaperecorder.Onceinthebase,Dr.Russellisinformedbyhisfather-in-lawandgeneralthatthetenfirstsatelliteshadmysteriouslyfeltonEarth.WhenDr.Russelldecodesthemessage,heencountersthealiensthataskhimtoscheduleameetingwiththeleadersofEarthinWashingtonin56dayswiththeintentiontoinvadeEarthwithoutpanickingthepopulation.Dr.Russelldevelopsananti-magneticweaponthatbecomesthatlasthopeofhumanraceagainstthehostilealiens.