Beauty Cookson is no beauty. She's a plain, timid girl who constantly feels inferior to the super-confident, snooty girls at school. Worse than the teasing in the playground, though, is the unpredictable, hurtful criticism from her father. Beauty and her meek, sweet mother live in uneasy fear of his fierce rages, sparked whenever they break one of his fussy house rules.

Ruby and Garnet are ten-year-old twins. They're identical, and they do everything together, especially since their mother died three years earlier – but they couldn't be more different. Bossy, bouncy, funny Ruby loves to take charge, and is desperate to be a famous actress, while quiet, sensitive, academic Garnet loves nothing more than to curl up with one of her favourite books.

Ellie is nearly 13, in Year Nine, and desperate to have a boyfriend. Her best friends Magda and Nadine (both prettier and thinner) have boyfriends, but the closest she can get is Dopey Dan, who is younger and a real swot. Find out all her secrets, squirm at her most embarrassing moment, have a laugh, and discover more about boys!

Fourteen-year-old Prue and her sister Grace have been educated at home by their controlling, super-strict father all their lives. Forced to wear Mum's odd hand-made garments and forbidden from reading teenage magazines, they know they're very different to 'normal' girls – but when Dad has a stroke and ends up in hospital, unable to move or speak, Prue suddenly discovers what it's like to have a little freedom. Sent to a real school for the first time, Prue struggles to fit in.

Is anything bothering you? Problems in class or at home? Don't know where to turn for help? Log on to the Worry Website! Type in your worry and wait for the good advice to flow in. At least that's the plan when Mr Speed sets up his super-cool new Worry Website for the class. Holly, Greg, Natasha and the rest feel that they've got shed loads of worries but, as they find out, sometimes the best advice comes from the most unexpected place.

"Where do baby apes sleep? In apricots! I'm Elsa, and that's one of my jokes (I tell LOTS of jokes and I'm going to be a big star one day). I do my best to cheer my family up - but no one seems to laugh much any more. Not since we lost our lovely house and had to move into a bed and breakfast hotel."

Gemma and Alice were born on the same day and have been devoted best friends ever since. Despite Gemma's larger-than-life personality and Alice's quieter, calmer character, the two are inseparable – until Alice has to move house, all the way to Scotland. Gemma is utterly distraught, particularly at the thought that Alice might find a new best friend. Is there anything Gem's brothers, or perhaps her Grand dad, can do to help?

When my parents split up they didn't know what to do with me ... My family always lived at Mulberry Cottage. Mum, Dad, me – and Radish, my Sylvanian rabbit. But now Mum lives with Bill the Baboon and his three kids. Dad lives with Carrie and her twins. And where do I live? I live out of a suitcase. One week with Mum's new family, one week with Dad's. It's as easy as A B C. That's what everyone says. But all I want is to go home – back to Mulberry Cottage...

India lives in a large, luxurious house with a mum she can't stand and a dad she adores, though he hasn't had much time for her recently. She seeks solace in her journal, which she keeps in sincere imitation of her heroine, Anne Frank. Treasure lives on the local council estate with her loving and capable grandmother. She is devoted to her nan but lives in fear of having to go back to live with her mother and violent stepfather. A chance meeting sparks a great friendship between the girls.

Dolphin adores her mother, Marigold. She's got wonderful clothes, bright hair and vivid tattoos all over her body – a colourful lady, to match her colourful life. But Dolphin's older sister, Star, is beginning to wonder if living with Marigold's fiery, unpredictable moods is the best thing for the girls.

Dixie is the youngest Diamond girl. She and her sisters – dreamy Martine, glamorous Rochelle and tough Jude – could hardly be more different, but their mum has always tried to teach them the value of sticking together. Now Mum's expecting yet another baby, and she's convinced this one's a boy. She insists they move to a bigger place – but it's rough, dilapidated and filthy, and before they've even unpacked, Mum's gone into labour!

Sylvie and Carl have been friends since they were tiny children. They've always played together, called each other boyfriend and girlfriend and, deep down, Sylvie has always believed that they'd end up married to each other. They even have a magical fantasy world that belongs to them alone.

Floss's parents are divorced, and she divides up her week, spending five days with her mum, her new step-dad and her baby half-brother. The other two days Floss spends with her dad, helping him to run his greasy spoon cafe. But their simple arrangement is thrown into disarray when Floss's mum decides to move to Australia. Making the difficult decision to stay at home, Floss moves in permanently with her dad and they muddle along happily together, surviving on chip butties and enjoying visits to the local funfair.

Em adores her funny, glamorous dad – who cares if he's not her real father? He's wonderful to her, and to her little brother Maxie and sister Vita. True to form at Christmas, Dad gives them fantastic presents, including a real emerald ring for his little Princess Em.Unfortunately he's got another surprise in store – he's leaving them. Will Dad's well-meaning but chaotic attempts to keep seeing Em and the other children help the family come to terms with this new crisis?

Being a sister isn't always easy ... but what's the very worst thing about your sister? Marty and her sister Melissa couldn't be more different. Marty loves her Converse trainers, playing football, hiding in her secret den and helping her dad with his DIY. But Melissa loves Justin Bieber and all things pink, girly and pretty. The sisters can manage to live together, despite their occasional scraps but then Mum tells them they have to share a room.