Atthebeginningof2259，CaptainJohnSheridanreplacesSinclairasthemilitarygovernorofthestation.HeandthecommandstafflearnthatthedeathofPresidentSantiagowasactuallyanassassinationmastermindedbyVicePresidentClark（whoassumedthePresidencyuponSantiago'sdeath）.AconflictdevelopsbetweentheBabylon5commandstaffandthePsiCorps，anincreasinglyautocraticorganizationwhichoverseesandcontrolsthelivesofhumantelepaths.CommanderIvanova，thesecond-۾-commandofthestation，issecretlyalatenttelepathwhohasillicitlyavoidedregisteringwiththePsiCorps.TheShadows，anancientandextremelypowerfulracewhohaverecentlyemergedfromhibernation，arerevealedtobethecauseofavarietyofmysteriousanddisturbingevents，includingtheattackontheNarnoutpostattheendof2258.CentauriAmbassadorLondoMollariunknowinglyenliststheiraidthroughhisassociationwiththemysteriousMr.MordenintheongoingconflictwiththeNarn.TheelderlyandailingCentauriemperor，longanadvocateofreconciliationwiththeNarn，diessuddenlywhilevisitingBabylon5.Anumberofconspirators，鰭小號伊尼dingLondoMo llariandRefa，takecontroloftheCentaurigovernmentbyassassinatingtheiropponentsandplacingthelateemperor'sunstablenephewonthethrone.TheirfirstactistostartopenaggressionagainsttheNarn.Afterafull-scalewarbreaksout，theCentaurieventuallyconquerNarninabrutalattackinvolvingmassdrivers，outlawedweaponsofmassdestruction.Towardstheendoftheyear，theClarkadministrationbeginstoshowincreasinglytotalitariancharacteristics，clampingdownondissentandrestrictingfreedomofspeech.TheVorlonsarerevealedtobethebasisoflegendsaboutangelsonvariousworlds，includingEarth，andaretheancientenemiesoftheShadows.TheyenlisttheaidofSheridanandtheBabylon5commandstaffinthestruggleagainsttheShadows。