Open Water is a 2003 drama psychological horror film loosely based on the true story of an American couple, Tom and Eileen Lonergan, who in 1998 went out with a scuba diving group, Outer Edge Dive Company, on the Great Barrier Reef, and were accidentally left behind because the dive-boat crew failed to take an accurate headcount. The film was financed by writer/director Chris Kentis and his wife, producer Laura Lau, both avid scuba divers. The film cost $130,000 to make and was bought by Lions Gate Entertainment for $2.5 million after its screening at the Sundance Film Festival. Lions Gate spent a further $8 million on distribution and marketing. The film ultimately grossed $55 million worldwide (including $30 million from the North American box office alone).