Siobhán, a marine biology student, joins the crew of a trawler in order to complete her studies. As an academic, Siobhán is out of place and clumsy in this environment. A few hours offshore, the trawler ploughs into something uncharted. Panic rises — they are adrift with no radio, helpless and hopelessly entangled. As tempers fray, Siobhán tries to analyse the life form. Only as the crew begin to suffer a gruesome fate, does Siobhán realise what the creature wants. She must find a solution fast, if the crew are to survive.