S1, E4: Determined to find her half-sister, Charlie sets off for London, accompanied by Samy. While visiting the Sherlock Holmes Museum, Charlie meets Tracy Sheraton, a psychotic girl who begs her for help: her sister's ghost has come to warn her that she is in great danger. For her parents, Betty - a famous actress - and Joseph - a devoted stay-at-home dad - Tracy's erratic behaviour resembles in every way the first signs of dementia in their eldest daughter Emma, who committed suicide three years earlier. Weakened by a meeting with April Moriarty, her half-sister, which doesn't go as well as she'd hoped, Charlie takes refuge in Samy's arms, but is soon caught up in the investigation. She must save Tracy. Samy's medical skills come in handy now more than ever to prove that Tracy is not crazy and that Emma is still alive. They save Tracy from internment by proving that the Sheraton girls were poisoned by their father.