'Seeing I', written by Jonathan Blum and Kate Orman, features the Eighth Doctor and Sam.
Back Cover Blurb
He has no idea why Samantha Jones ran away from him.
Sam is homeless on the streets of the colony world of Ha'olam trying to face what's just happened between her and the Doctor. He's searching for her, and for answers. While she struggles to survive in a strange city centuries from home, the Doctor comes across evidence of alien involvement in the local mega-coporation, INC - and is soon confined to a prison that becomes a hell of his own making.
Where did INC's mysterious eye implants really come from? What is the company searching for in the deserts? What is hiding in the shadows, watching their progress?
Faces with these mysteries, separated by half a world, Sam and the Doctor each face a battle - Sam to rebuild her life, the Doctor to stay sane. And if they do find each other again, what will be left of either of them?