The final book is entitled "Nothing O'Clock", and features the Eleventh Doctor and Amy Pond. The synopsis is below:
Thousands of years ago, Time Lords built a Prison for the Kin. They made it utterly impregnable and unreachable. As long as Time Lords existed, the Kin would be trapped forever and the universe would be safe. They had planned for everything… everything, that is, other than the Time War and the fall of Gallifrey. Now the Kin are free again and there’s only one Time Lord left in the universe who can stop them!
The eBook will be released on the 21st, priced at £1.99, A paperback anthology (£12.99) of all eleven stories and an audio download collection (£14.99) will also be released.