The Darksmith Legacy

The Darksmith Legacy is a ten book series featuring the Tenth Doctor and published by BBC Children's Books.

The series
The overarching plotline concerns the Eternity Crystal and the Darksmiths. The line of books has interactive elements, readers having the options to go to the tie-in website to add points to a tally of points accumulated so as to access additional content.

Features
Apart from the fiction, the books have TARDIS Data Banks containing more information and activity pages designed to tie in with the websites. Additionally, the books have cut-out or downloadable coupons entitling readers to an invitation to a party in London, provided they had completed the challenges.

Each book ends in a cliffhanger leading on to the next segment of the storyline.