Severalyoungcouplestraveltoaprivateislandforamysterioustrainingretreatthatpromisestostrengthentheirrelationship.However,duringtheRetreat,theheroesencounteranancientdemon-aSuccubus.Thismonsterfeedsonthelifeenergyofpeople,takingonsomeoneelse'sappearanceandprovokingvictimstoshowtheworstqualitiesanddoterriblethingseee