This programme meets the people whose ambition and creativity have no limits as they strive to achieve the world's most extraordinary Christmas dinners. Nasa astronaut Anne McClain will be spending Christmas day on the International Space Station. Each meal that she has in space has to be carefully selected and prepared in advance, so she and the food technicians go through every meal while she's still on Earth, and hope that it tastes as good in zero gravity. On a nuclear submarine at the bottom of the ocean, 150 submariners tuck in to a Christmas dinner that was carefully prepared and stored before the sub set off. Their mission is so secret that on Christmas Day only six crew members have any idea where in the world they are.