Isobel Jekyll & Margaret Hyde is a French-British animated comedy horror series based on the characters created by Mike Absalom.
Plot[]
Mike Utterson is a 12-year old jewish boy living with his mother Zoe Utterson where, one week, he learned that Zoe is getting married to scientist Henry Jekyll, making Isobel, his classmate, his step-sister. One night, while Mike was getting ready for bed, he noticed Isobel transform into Margaret Hyde (along with her father, turning into Edward Hyde) as he chased her out of the house and calmed her and Edward down before taking them home.
Mike is a boy living with a girl who can transform into a physical and mental manifestation of her evil personality due to the serum her dad developed to mask hidden evil.