Doctor Who: The Castle Of Fire is a 2009 special featuring the Eighth Doctor and a companion called Joanne Flags.
It depicts an alternative way of how the Eighth Doctor regenerates into his Ninth incarnation.
It begins as the Doctor time travels to the castle age. He meets and befriends a peasant named Joanne Flags who is 17 years old.
People say there is a dragon somewhere by the castle. Late at night the Doctor and Joanne investigate. They see a large red dragon named Grato whom has been living since the stone age and was created by evil druids. He is planning to kill the people in the kingdom and the Doctor and Joanne have to stop him.
Near the end of the movie the Doctor fights Grato and he gets beat up and he is pushed off the castle by Grato. Then they continue fighting and the Doctor is blasted with fire. He has fire burns on his chest and he has one on his cheek. He is nearly dead. He falls over but Joanne helps him up and he uses regeneration energy to create lightning and shock Grato.
Then he regenerates into the Ninth Doctor.