She is Alex Rider's guardian,because she quatoue "I've been living with you for nine years" He remains uncertain as to what her nickname Jack is actually short for, as she never confirms her full name with him although he's asked her numerous times. She is mentioned sometimes when Alex does difficult tasks like when he was using his crane to stop the drug dealers. He said she helped him get a teddy bear.
Seven years before the start of Stormbreaker, she came to Britain. She struggled to receive a visa (mentioned by the MI6 director Alan Blunt), before Ian Rider employed her to look after Alex. At the final book scorpia rising she got killed by a bomb.