forever as one

One day the Doctor get a message from an an known source, that a girl from a parallel universe some how found a way though. The doctor has to find the girl and fix the crack. But along the way they find out more than he expected. Could this girl be the long lost time lord? If so how did she end up in the parallel universe and get back with out a Tardis? Marie Scott thought she was a normal girl but one small stone changes her life forever, when she finds herself on the run with a man who calls him self the Doctor and his friend Rose Tyler. She is scared of what is to come but she has the Doctor and that is all that matters, right?