Threeillegaldrugdealerslaunchedoutonavoyageinahomemadesubmarine.Thesubmarineworkedwellinitially，butitstartedtomalfunction.Inattemptingtoreducetheweightsomehow，theywereinvestigatingthecargosectionwhentheydiscoveredayoungfemale，Reina，hiddenthere，andshelookedappalling.Asthesituationgetsworse，thetensionsamongthethreemenareheightened，andinthemidstofthis，Reinaattemptstoescape，butshehasnowheretogointheendlessopensea. Withanunusualsettingofthesubmarine，wherenothingcanbeseenotherthanthehorizon，Submersiblecapturesthetensionoftheconflictsbetweenthecharactersandtheirstruggleforsurvival，whilethesubmarineenvironmentitselfarousesextremeclaustrophobiaandanxiety.ThetopstarfromColumbia，NataliaReyes，whoattractedtheworldwidefilmindustry’sattentionwithCiroGuerra’sBirdsofPassage(2018)，andmadeherHollywooddebutinTerminator∶DarkFate(2019)，onceagaindrawsattentioninherroleasReina.(JinPARK)