Home in the stars

Thirteen-year-old Tal is the first person to go Earth for almost forty years, well except for everyone else that's still living there of course. On Tal planet (Eart2.05) scientists have discovered that earth actually didn't explode and has been entirely repopulated, and Tal has been picked to go back down and live with someone that was 'left behind' all that time ago. Of course, there are some problems, her host doesn't remember anything about her past and thinks Tal is her daughter; Clemintyne.
But Tal's biggest problem is that no one believes a word she says about...well anything really.