British marathon swimmer and world record holder Beth French sets out to swim across seven of the world's most dangerous sea-channels – an extreme challenge called Oceans Seven – and do it in record time: within one year. Driven by her desire to set an example for her autistic son and to overcome a life-long, debilitating illness, Beth travels to far-flung corners of the world confronting hypothermia, sharks, jellyfish and wild weather as well as her own inner demons. But, in an unpredictable and emotional climax, Beth’s yearning to conquer the open sea comes into heart-rending conflict with a mother’s dreams for her son.