Jesamine Osbourne (Jess for short) lives in Twinbrook with her mother, Jill Osbourne, her father, Jack Osbourne, and her brothers, who are identical twins, Marty and Ross Osbourne and baby sister, Maddy Osbourne.
Jess has never moved from Willow Manor, where the family lives now. She was born in the local hospital, but was hurried home as soon as it was possible. She was treated very well as a baby, barely crying once. As a toddler she learnt all her skills, walking and potty from Jack, and talking from Jill. When she was a child, though, she found it hard to maintain her good childhood, as she was getting bullied by the evil Jeffrey Castor, causing them to dislike each other. She only managed a C. She said that she would try and start again as a teen, but Jill didn't really believe her.
On the last day of the summer holidays, Jess was bored and decided to go to the Racket family house. There she met Max, who took her inside, where she met Shark Racket. The pair hit it off immediately and found each other attractive. FInally, she had to leave at her curfew, but she had had her first kiss, and had entered her first relationship.
Contrary to what she said about 'turning over a new leaf' on her birthday, Jess earned detention on the first day of school for sleeping in class. Jill was very cross, and grounded her until the weekend. Jess was annoyed about this because in detention she and Shark had planned to meet up the next day. However, Shark was determinned to come home with Jess after school so he did. Jill was a little scared of him and his family, so she didn't stop them. That day, Jess proposed going steady with Shark, and he eagerly accepted. Not long after this, she came home from school to find her mother settled on the sofa, with dad stroking her blonde hair. Jess immediately knew that Jill was pregnant again. Jess only knew because they had been in the exact same poses as when she had found out about Marty and Ross. She groaned and went to do her homework. However, when she finally met Maddy, she adored her. The twins would often come into her room to wake Jess up when Maddy was crying, because they knew that she would be able to quieten her down. They became fast friends!