I think the lady who picked up the ring is the Rani.

Not the descendant of a woman John Smith fell in love with.

Who's to know that the Master hasn't split himself in two using DNA (like that seen in Journeys end,with the Metacrisis.)

The Master could be Harold AND Lucy Saxon....she shot the other half of her then went to pick up the ring containing the regenerative energy. The Master is sly and from some of the new pictures...Lucy Saxon is back and dressed in RED.

I also think Donna will have a slight relapse when she reads the Verity Newman book and then reads the 'Fighting the Future' book,by another author.

The Doctor and Wilf go to investigate the authors Mansion house and find that Lucy Saxon is behind the book.

Meanwhile, the Master befriends Donna Noble and becomes her boyfriend. He goes for a pretty boy look and bleaches his hair. He wants to drain Donna of all the information she obtained in the metacrisis.......

This is what i think will happen so far. I am only speculating.

Apparently, the Doctor meets a descendant of Joan Redfern (Human Nature / The Family Of Blood) who has published John Smith's writings and illustrations: the Doctor's adventures in time and space have been published and he's more than a little upset about it.

To make matters worse, the Master has returned (which seems logical to assume after Carmen's cryptic warning in 'Planet Of The Dead' and sightings of John Simm during filming). The Doctor needs all the help he can get, so gains assistance from Rose, Martha, Sarah Jane, Luke, Wilfrid, Jack and the Torchwood team (not sure about Donna at this moment in time).

And from the looks of things, the Doctor takes two possible temporary companions to Earth from Mars, one being a lady by the name of Adelaide and the other being a young East European gentleman (whose character name remains unknown).