A Wily Old Serpent And His Human Family

The Doctor regenerates into his fifteenth face (or sixteenth, depending on if he feels like counting the War Doctor - seventeenth if he counts when he went back a couple of regenerations and eighteenth if he counts when the Master became him), but something is clearly different.
When his past starts to jeopardise his companions' futures, things get all the more dangerous.
Will the Doctor truly come out on top this time? Or will he lose himself or his loved ones to the Oncoming Storm and the Master's plans?