The kid who dreamt it all (Doctor Who fanfiction)

Jo Collins was 2 and had the IQ of Steven Hawking when she first met the doctor. 11 years later, she meets the man who saved her and her sister's life and begins to travel around time and space with him. But as their adventures get even more daring as they go on, the Doctor begins to wonder if Jo is the ordinary human she looks or if she's something more!