Rising Tide (2011)

Coming-of-age thriller following a group of college graduates who go on a camping trip to celebrate the end of their studies. The group head to the tidal island of Lindisfarne, accompanied by their new friend, Izzy. When dusk closes in sooner than expected they set up an impromptu camp. It is not long before their trip turns into a nightmare, however, when Izzy's disastrous past follows her to the island...