In her third adventure, Cookie finds mysteries everywhere - but can she solve them, and save the science show? Hurray, Cookie's Nani is coming to stay from Bangladesh! But she doesn't speak English and Cookie is the only one in the family who doesn't speak Bengali. Luckily, science-mad Cookie realises that her coding lessons at school might help her crack the language code and help her bond with Nani. Other mysteries are harder to solve, though - like, why is Jake's mum acting so weird? Who is the mystery gamer who keeps levelling-up in Cookie's computer game? And who is the Woodburn Hacker, who keeps posting teachers' secrets on the school website? Why does it look like it might be Cookie herself? Can Cookie solve these mysteries, clear her name and save the science show?