It's late on Friday night when Casey's mobile starts to ring. She is expecting it to be her daughter, Riley. But it isn't Riley. It's a woman from the Emergency Duty Team. So begins Casey and Mike's latest fostering challenge - a 15-year-old girl called Keeley who's run away from her long-term foster home 25 miles away.

The Jonathan Ross Show has just started when Casey gets the call. She thinks it will be Riley - telling her that her favourite actor is going to be on TV. But it's something far more urgent: a 15-year-old girl who has run away from her foster family and accused her foster father of sexual abuse. The family deny it vehemently, but such an allegation can never be taken lightly, so a new home must be found for Keeley.

Keeley is polite, but she's sharp, and she has all the hallmarks of a child who has been in the system a long time and knows how to play it. Whether the allegation is true or not, Casey knows there will be no winners here. If it is true, then a young girl's life has been torn asunder. If not, then the heartache for the family will be surpassed only by the bleak outlook for Keeley.

In the short term, it's a case of providing a safe, supportive home for a vulnerable child. But with the dangerous world of the internet at her disposal, it seems this strong-minded youngster has her own ideas of where that safe place should be....