I started a new story… again.
https://archiveofourown.org/works/69718566/chapters/180893206
Janie and Jack have had a quiet life in the safe walls of St. Luke's University in the love and care of their parents, Rose Tyler and the Doctor- but when a 'one hour trip' keeps them away unexpectedly for days, the kids find themselves navigating the unknown- facing younger versions of the people they know best. They must stick together, keep their true identities secret, and rely on their wits to protect themselves and the delicate timeline. Every move is careful, every word measured, because revealing who they are could change everything- or end their world as they know it before it can ever begin.
Twelve and Rose's children worry when they don't make it home in their normal time when answering a distress call, so they run away from Nardole to find their younger parents, Nine and Rose, to ask for help- but their parents aren't even a couple yet.