A 5-year-old boy, Ethan, is brought to Casey in the middle of the night after the sudden death of his young mother after a drug overdose. Estranged from her parents, Ethan’s mum had been abused by her ex-partner, and began taking drugs to cope. Ethan is obviously lost and bewildered, and regularly wakes up screaming for his mum in the night. He begins to lash out at other kids at school and his behaviour becomes more volatile.

Casey Watson is back, doing the job she does best - rolling up her sleeves and fostering the children who, on first meeting, seem like hopeless cases. But when she meets Miller and discovers the truth about his disturbing childhood, even Casey begins to doubt if this child will ever be able to accept love. Found naked and alone on a railway track, Miller was just five when he was first admitted into the care system.

After taking a few weeks off work, Casey is presented with a new foster child: 14-year-old Elise, whose Mum left her at just five years old. At first, she’s no trouble at all, that is until she falsely accuses another carer, Jan, of acting inappropriately towards her. It turns out this isn’t the first lie Elise has told—her previous carer was constantly following up allegations Elise had made of people bullying her, trying to have sex with her or hurting her physically.

Brought to Casey as a short-term emergency placement, 14-year-old Adrianna arrives with nothing but her gratitude. Having turned herself in to a social services office some 100 miles away, she has no possessions, no English and, apparently, no history - not that she's willing to share, anyway. She is a beautiful young Polish girl, with the bearing of a ballerina, but is terrified, malnourished and unwell.

Harley, 13, has been sectioned under the mental health act after attempting suicide. She was spotted climbing the railings on a footbridge that crossed a busy motorway and pulled to safety by a member of the public. After six weeks in hospital, social services are looking for a short-term placement so she can be kept safe while family therapy takes place. Harley has a family - a widowed mother and an older sister, Milly, who left home with her long-term boyfriend just over a year ago.

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.

Casey's Unit is, as ever, full of troubled, disaffected pupils, and new arrival Leo is something of a conundrum. Thirteen-year-old Leo isn't a bad lad - in fact he's generally polite and helpful, but he's in danger of permanent exclusion for repeatedly absconding and unauthorised absences. Despite letters being sent home regularly, his mother never turns up for any appointments, and when the school calls home she always seems to have an excuse.

It's the night before Christmas when Casey and Mike get the call. A 12-year-old girl, stuck between a rock and a hard place. Her father is on a ventilator, fighting for his life, while her mother is currently on remand in prison. Despite claiming she attacked him in self-defence, she's been charged with his attempted murder. The girl is called Bella, and she's refusing to say anything. The trouble is that she is also the only witness....

Just when Casey thinks her foster care duties are done, she’s asked to look after Sam, a troubled nine-year-old with a violent streak who drove his previous guardians to release him of their care. It soon unfolds, however, that this is no simple case. Determined to get to the root of Sam’s behaviour, Casey is committed to uncover his mysterious past only to find out something far darker than she ever imagined.

Nine-year-old Archie and his five-year-old sister, Bobbi, are taken into emergency police protective custody after an incident of domestic violence at their family home. Rosie collects the children from their out-of-hours foster carer on New Year's Day and instantly recognises Archie from a domestic violence workshop she helped with. Rosie remembers that when asked what he enjoyed most about the course, Archie said, 'The biscuits'. Social workers are concerned that Archie and Bobbi have been neglected.

Named after the lager that christened her at birth, Stella's life is characterised instability and neglect. Her teenage mother abandons her in the first few weeks of her life, and left in the 'care' of her father, she ends up lying deserted in a house with no food, no water, no clothes and no warmth. She eventually lands in the care of foster carer Louise, who is determined to change her life for the better.

Experienced foster carer Rosie Lewis takes on the heart-breaking case of Megan, a baby born with neo-natal abstinence syndrome and a cleft palate. Addicted to drugs from birth because of her mother's substance abuse during pregnancy, new-born Megan is taken into Rosie's loving care. Rosie is supposed to help Megan find her new permanent home, but it turns out that Megan has already found her 'forever mummy' in Rosie.

Born in a prison and removed from his drug-dependent mother, rejection is all that 7-year-old Alex knows. When Cathy is asked to foster little Alex, aged seven, her immediate reaction is: Why can't he stay with his present carers for the last month? He's already had many moves since coming into care as a toddler and he'll only be with her a short while before he goes to live with his permanent adoptive family. But the present carers are expecting a baby and the foster mother isn't coping, so Alex goes to live with Cathy.

The true story of two-year-old Anna, abandoned by her natural parents, left alone in a neglected orphanage. Elaine and Ian had travelled halfway round the world to adopt little Anna. She couldn't have been more wanted, loved and cherished. So why was she now in foster care and living with me? It didn't make sense.

Tilly hates her stepfather, Dave. He abuses her mother, but she refuses to leave him. Frightened for her own safety, Tilly asks to go into foster care and is placed with Cathy. Tilly arrives with a graze on her cheek, and Cathy becomes increasingly concerned by Dave’s behaviour, especially when she learns he has been showering Tilly with gifts. While she’s busy looking after Tilly and trying to keep her safe, Cathy is also worried about her own daughter, Lucy.