Lauren is smitten with Craig's friend Justin. Millie's seen it all before, but this time it's worse - her sister's fallen harder and further than ever! Something about Justin rings alarm bells for Millie, and her instincts are proved right when she finds out he's been using Craig to get to Lauren - and he's using Lauren, too. But nothing Millie or Craig say will get through - Lauren is hopelessly besotted. With Fran's help, Millie turns detective. Meanwhile, Dad realises Jake is growing up - but he misses their silly games, and realises something is up.