Several young couples travel to a private island for a mysterious training retreat that promises to strengthen their relationship. However, during the Retreat, the heroes encounter an ancient demon - a Succubus. This monster feeds on the life energy of people, taking on someone else's appearance and provoking victims to show the worst qualities and do terrible things.

　　Two sisters living separate lives on different continents are reunited on a Mediterranean Island. The two barely have time to bond and revive family ties as Kate, the elder, meets a group of locals and agrees to an exciting ride on a hot air balloon. But disaster strikes and as the result of a freak accident, the balloon is carried far out to sea. Their cell phones out of range, and the balloon running out of gas, Kate and her friends are battling for their lives. While, back on land, the younger sister, Liz, has become an unwanted "material witness" to a crime. Matters then take a dramatic twist, one that will mark their lives forever.