Ayoungnewlywedcouplefindthemselvestrappedinanetworkofundergroundcaves.Withherhusbandinjured,thenewbrideisforcedtofindherwaybacktothesurfaceinordertosavehislife.Intheprocess,theydiscoveraterrifyingtruthaboutthequot;underneathquot;,theyarenotalone.Somethingevilishuntingthem.