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. Unfortunately, as the story develops, it just becomes more and more preposterous and I began to hope there were sharks in the water. There are some rather pointless familial flashbacks intercut with the main theme that bring in their dad to the equation - I suppose to give us some indication as to why their relationship with each other (and with the water) is not what it might be, but the repetitive nature of the narrative soon wears thin and the original promise that there is only 20 minutes worth of oxygen left in her tank started to suggest that this might have worked better were it just a short film rather than a full length feature. I am not sure I'd bother if I were you.