Siblings "May" (Louise Krause) and "Drew" (Sophie Lowe) appear to have rather an uneasy relationship as they drive along a dirt track to dive off a remote section of coastline. All goes fine, until a sudden rockfall traps the former underwater and leaves the latter tasked with finding ways to replenish her sister's dwindling oxygen supply and get the boulder off of her foot! There are times when this film is actually quite funny - I really hope they had insurance for their hire car - and the underwater photography helps to generate quite a sense of the perilously claustrophobic at times.…