AbigailClayton獨自一人生活，已將近20年沒有離開她的公寓。當她的鄰居死亡，偵探FrankGiardello登門造訪展開調查，她原本秩序井然的世界開始瓦解。AbigailClayton獨自一人生活。一個人非常孤獨。實際上，這位女繼承人沒有離開她的曼哈頓公寓已將近20年。當她年邁的鄰居死亡促使紐約市警察局兇殺案偵探FrankGiardello登門造訪展開調查，內心恐懼不安的AbigailClayton看到那位偵探在她門外，詢問她。AbigailClayton曾試圖收購現在空置的那個公寓以確保她的隱私，當新租戶莉蓮和查理搬進來時就更加煩惱了。AbigailClayton焦急地從她的前門的安全窺視孔監視她的新鄰居，但當她終於面對面地遇到了莉蓮和查理時她原本秩序井然的世界開始瓦解，她庇護的存在也開始成爲意外和恐怖的方式威脅着。Anheiresswho’sbeenshutinsideherapartmentbuildingfornearlytwodecadesisforcedtoconfrontherfearsafteroneofherneighborsiskilledandadetectivearrivestobegintheinvestigation.AbigailClaytonlivesalone.Veryalone.Infact,theattractiveheiresshasnotleftherManhattanloftapartmentforalmosttwodecades.Thefamousdaughterofawealthyindustrialist,Abigaildisappearedfromthepryingeyesofthepressandtheintrusivenessofherfamilyonher18thbirthday,thedayshereceivedhermassiveinheritance.Duringyearsofself-imposedisolation,Abigailhashadcontactwithonlytwopeople-herbuilding’sConcierge,Klandermann,withwhomshecommunicatesvianotes-andDr.RaymondFontaine,alongtimefamilyfriendandhersoleconfidantformostofherlife.WhenthedeathofherelderlyneighborpromptsNYPDHomicideDetectiveFrankGiardellotolaunchaninvestigation,theagoraphobicAbigailisdistressedtofindhimoutsideherdoor,askingtoquestionher.Havingtriedtoacquirethedeadwoman’snowvacantapartmenttoensureherprivacy...AreclusiveManhattanheiressfindshercarefullystructuredworldbeginningtocrumbleafterherelderlyneighbordies,andayoungcouplemovesintothevacantapartment.Onher18thbirthday,AbigailClayton(SelmaBlair)receivedastaggeringinheritancefromherlatefather,anaffluentindustrialist.Thatsameday,Abigailalsoescapedtheprobinglensesofthepaparazzibysealingherselfawayfromtheworldinhermassiveloft.Nearlytwentyyearslater,theonlypeopleAbigailinteractswithareKlandermann(KevinPollak)theConcierge,andDr.RaymondFontaine(BeauBridges),atrustedfamilyfriend.Oneday,Abigail’selderlyneighbordiesundermysteriouscircumstances,andHomicideDetectiveFrankGiardello(GiovanniRibisi)comesknockingonAbigail’sdoorlookingforanswers.Concernedthattheopenapartmentcouldprovideaperfectperchforpryingeyes,Abigailinquiresaboutpurchasingittonoavail.Shortlythereafter,AbigailspiesCharlie(JasonLee)andLillian(AmySmart)movingintotheapartment.Intheweeksthatfollow,Abigailbeginsreligiouslyusingherpeepholetoscrutinizehernewneighbors’everymove.Butshecan’tstaylockedawayforever,andthemomentAbigailmeetsCharlieandLillianinperson,thenightmarebegins.AbigailClayton(SelmaBlair)livesalone.Veryalone.Infact,theheiresshasnotleftherManhattanapartmentforalmosttwodecades.WhenthedeathofherelderlyneighborpromptsNYPDHomicideDetectiveFrankGiardello(GiovanniRibisi)tolaunchaninvestigation,theagoraphobicAbigailisdistressedtofindhimoutsideherdoor,questioningher.Havingtriedtoacquirethenowvacantapartmenttoensureherprivacy,AbigailisfurtherupsetwhennewtenantsLillian(AmySmart)andCharlie(JasonLee)movein.Abigailanxiouslymonitorshernewneighborsfromthesafetyofherfrontdoor’speephole,butherwell-orderedworldbeginstounravelwhenshefinallyencountersLillianandCharlieface-to-faceandhershelteredexistencebecomesthreatenedinunexpectedandterrifyingways.