The Defector's Daughter

Sarah is profoundly repressed as a misdiagnosed autistic child. After treatment she blossoms into a kinky green-haired teenage prodigy confounding Cambridge Professors in a brilliant interview to read mathematics and cryptology at Russell College.
Her devoted father, David, is a misfit in naval intelligence, who is kidnapped in Budapest by a brutal ISIS regime, and threatened with dismemberment. He is befriended by Maryam, an enslaved Arabic tutor, converts to Islam to save his life, marries Maryam and defects to ISIS.
Sara finds that Russell College is a covert centre for espionage recruitment and training controlled by corrupt MI6 master spies. Sara becomes entangled in undercover missions, whilst seeking respite for her wayward father. She reveals her inner thought through bizarre candid diaries.
Sara, Maryam and David find solace in their peaceful country retreat in Sussex, but become caught in the crossfire between the MI6 mafia and barbarous ISIS thugs.
The terrified family become engulfed in a series of chilling attempts at their liquidation.