Severalyoungcouplestraveltoaprivateislandforamysterioustrainingretreatthatpromisestostrengthentheirrelationship.However, duringtheRetreat, theheroesencounteranancientdemon-aSuccubus.Thismonsterfeedsonthelifeenergyofpeople, takingonsomeoneelse’sappearanceandprovokingvictimstoshowtheworstqualitiesanddoterriblethings.！