It's Christmas and the Welsh contingent have been invited to celebrate the festive season with the Shipmans. So, with the help of Dave and his coach, Nessa and the Wests head east.In Essex, Dawn and Pete are round for drinks. Mick is preoccupied with the new love of his life, a handsome Norfolk bird, and Smithy cannot wait to spend his first Christmas with Neil the baby.Pam has done a fabulous spread, Bryn has got his mistletoe at the ready and everything looks set to be a cracker of a Christmas. But 'tis no longer the season to be jolly when the bubbly starts flowing and the Christmas spirit gets a grip, and Gavin and Stacey make a startling announcement that will rock their Barry and Billericay boats.