
I was thinking about companion’s first episodes in New Who, and that one scene there always is in which they prove themselves and become the Companion. And thinking about it, these scenes often reflect both the season finale and the role the companion has in the Doctor’s life.
Rose in Rose grabs onto a rope, not exactly sure of what she is doing, and saves the Doctor. And Rose in season one, not exactly sure of what she is doing, saves the Doctor. Literally when she stares into the heart of the TARDIS, but through the season she also saves him emotionally from his post Time War state of misery.
Martha, in an act of faith in the Doctor, gives her last breath to the Doctor so he can save the planet, which reflects Martha’s journey in which she gives everything she has to give, and through her own faith in him, puts the Doctor in the position where he can save the world. And I do think that Martha support, at great personal cost to herself and later her family, is the only thing holding the Doctor together through season three.
And then there’s Donna, who proves herself by simply providing exactly what is needed, when it is needed. And I think that’s what Donna’s role is going to be in the Doctor’s life, to provide what he needs – whether it is emotional support or a swift kick up the backside. And, of course, following my theory, Donna is going to provide exactly what is needed in the season finale to save the day. We’ll just have to wait to find out what it is.