In2261,theVorlonsjointheShadowWar,buttheirtacticsbecomeaconcernforthealliancewhentheVorlonsbegindestroyingentireplanetswhichtheydeemtohavebeen"influenced"bytheShadows.Disturbedbythisturnofevents,Babylon5recruitsseveralotherpowerfulandancientraces(theFirstOnes)totheircause,againstboththeShadowsandtheVorlons.CaptainJohnSheridanreturnstothestationafterescapingfromZ'ha'dum,butataprice:barringillnessorinjury,hehasonly20yearslefttolive.HeisaccompaniedbyamysteriousaliennamedLorienwhoclaimstobetheoldestsentientbeinginthegalaxy.HoursbeforeSheridan'sreturn,Garibaldiisrescuedandreturnedtothestation,inratherdubiouscircumstances.HeismarkedlymoreparanoidandsuspiciousofotheralienracesandofSheridanthanhewasbefore.CentauriEmperorCartagiaforgesarelationshipwiththeShadows.LondoMollariengineerstheassassinationofCartagiaandrepudiateshisagreementwiththeShadows.LondokillsMr.MordenanddestroystheShadowvesselsbasedontheCentaurihomeworld,inanattempttosavehisplanetfromdestructionbytheVorlons.Aidedbytheotherancientraces,andseveralyoungerones,SheridanluresboththeVorlonsandtheShadowsintoanimmensebattle,duringwhichtheVorlonsandShadowsrevealthattheyhavebeenleftasguardiansoftheyoungerraces,butduetophilosophicaldifferences,endedupusingthemaspawnsintheirendlesswarsthroughouttheages.Theyoungerracesrejecttheircontinuedinterference,andtheVorlonsandShadows,alongwiththeremainingFirstOnes,agreetodepartthegalaxyforever.AftertheShadowsaredefeatedGaribaldileaveshispostassecuritychiefandworksonhisownasa"providerofinformation".HebeginsworkingforoneWilliamEdgars,aMarsTycoon,whoismarriedtoGaribaldi'sformerlove.WhileheworksevercloserwithEdgars,hebecomesincreasinglyaggressivetowardsSheridanandeventuallyleavesBabylon5.MinbarisgrippedbyabriefcivilwarbetweentheWarriorandReligiouscastes.DelennsecretlymeetswithNeroonoftheWarriorcasteandconvinceshimthatneithersidecanbeallowedtowin.Shetellshimthatshewillundergoaritualwhereinshewillbewillingtosacrificeherself,butwillstoptheritualbeforesheactuallydies.WhenNeroonseesthatsheactuallyintendstogothroughtheentireritual,herescuesherandsacrificeshimselfinstead,declaringthat,althoughhewasbornWarrior,inhisheartheisReligious.AspartoftheongoingconflictbetweenEarthandBabylon5,GaribaldieventuallybetraysSheridanandarrangeshiscaptureinordertogainEdgars'trustandlearnhisplans.GaribaldilaterlearnsthatEdgarscreatedavirusthatisdangeroustoonlytelepaths.Itisthenrevealed,thatGaribaldiwasactuallyabductedbythePsi-CorpsattheendofSeason3andre-programmedbyBestertoprovideinformationtohimattherighttime.BesterreleasesGaribaldiofhisprogramming,andallowshimtoremembereverythinghehasdonesincebeingkidnapped.Edgarsiskilledandhiswifedisappears,butisreunitedwithGaribaldiaftertheendofthewar.GaribaldihelpsfreeSheridanandreturnhimtothecampaigntofreeEarth.AnallianceledbyBabylon5freesEarthfromtotalitarianrulebyPresidentClarkinashortbutbloodywar.ThisculminatesinClark'ssuicideandtherestorationofdemocraticgovernment.Marsisgrantedfullindependence,andSheridanagreestoresignhiscommission.TheLeagueofNon-AlignedWorldsisdissolvedandreformedintotheInterstellarAlliance,withSheridanelectedasitsfirstPresidentandcontinuinghiscommandoftheRangers,whoaretoactasagalacticequivalentofUnitedNationspeacekeepers.Intheseasonfinale,theeventsof100,500,1000,andonemillionyearsintothefutureareshown,depictingBabylon5'slastinginfluencethroughouthistory.Amongsttheeventsshownarethepoliticalaftermathofthe2261civilwar,asubsequentnuclearwaronEarthinvolvinganewtotalitariangovernmentintheyearAD2762,theresultingfallofEarthintoapre-industrialsociety,thelossandrestorationofhumanity'sknowledgeofspacetravel,andthefinalevolutionofmankindintoenergybeingssimilartotheVorlons,afterwhichEarth'ssungoesnova.
《巴比伦5号第四季》是J. Michael Straczynski导演的作品，发行于1996年（美国），由Bruce Boxleitner,Michael O'Hare,Claudia Christian,Jerry Doyle,Mira Furlan等主演，飞飞美剧为大家提供巴比伦5号第四季1080P高清完整版免费在线观看，能在手机和电脑上流畅观看巴比伦5号第四季高清版（已完结英语原声），同时还支持是手机投屏。
已完结
