 The episode centers on the marriage of Torchwood employee Gwen Cooper ( Eve Myles ) to her long @-@ term partner Rhys Williams ( Kai Owen ) . The wedding is complicated by Gwen 's sudden <unk> by a shape @-@ shifting alien Nostrovite . Although she resolves to see her wedding through , her <unk> are interrupted by an attack from the biological mother of the alien fetus ( played successively by <unk> Brown , Nerys Hughes and John Barrowman ) . With the help of Rhys and Gwen 's Torchwood colleagues the fetus is neutralised and the attacking alien defeated . Gwen and Rhys marry , and their families have their memories of the wedding day wiped . 
