Overview: Lydia and Arg's relationship takes another unexpected turn. Billie and Cara hold an `EsSex and the City'-themed Valentine's Day party - and Billie bags herself a Valentine's kiss. Mario tries to get back into Lucy's good books with some surprise romantic treats, new boy Ricky adds to his female following by announcing that he is on the market, and Lydia goes house-hunting with her mum Debbie.