Every Doctor has those moments that define him. That reveal him, his values and ideals. That show he’s worthy of the name.

Of course, they’re also the moments where the actors prove themselves worthy. William Hartnell letting go of his only family. Tom Baker asking “Do I have the right?” David Tennant wrestling with his conscience so many times.

Peter Capaldi’s first series, of course, gave us a perfect I Am The Doctor moment with that speech in “Flatline.” It was that stand-up-and-squee moment we’d been waiting for all season, and for a little while it might have been the Twelfth Doctor’s defining moment.

Until now. Until a scene so powerful, a performance so perfect, that Capaldi needs only three words to break your heart.

Of course, it starts with the story. “The Zygon Invasion” and “The Zygon Inversion” (written by Peter Harness, with Steven Moffat joining him for the second part) is a geopolitical thriller that revisits the uneasy relationship between humanity and the Zygons.

You’ll recall that the last time they shared a room, in “The Day of the Doctor,” they were working out a peace agreement forced upon them by Ten, Eleven, and the War Doctor. To keep that truce, those same Doctors put a secret plan in effect, guarded only by two Osgoods – one human, one Zygon.

You’ll also recall that one of those Osgoods was killed by Missy in “Death in Heaven.” And the peace almost dies with her. But as “The Zygon Invasion” reveals, the other survived, and becomes pivotal in the events that follow.

When Osgood’s return was announced, there was a lot of “whaaaaa?” about how she could have survived. Would she be human? Would she be Zygon? The question is never really answered. And it’s to the credit of Harness, Moffat, and especially Ingrid Oliver that the answer doesn’t matter. What Osgood is doesn’t matter. It’s who she is that’s important. And Oliver is so good (as she’s always been) that you only recognize Osgood as Osgood.

(Tangent: That’s a lot of good for one paragraph…)

As to those events that follow, there’s a splinter group of Zygons who don’t recognize the peace. And in “The Zygon Invasion,” they launch their own war, to allow or force all the Zygons to live in their true form. Or to kill all the humans. Or to kill all the Zygons who don’t agree with them. Or to get unlimited rice pudding. It’s never really clear what they want. But that’s the point. And the lives of twenty million Zygons, most of them living peacefully, become pawns in their assault.

(Of course, in the process of the invasion, Clara is replaced by a Zygon. And Jenna Coleman has a lot of fun with Evil Clara – or Bonnie, or Zygella – even if her purpose and objectives are as vague as the reason she has to have her own name.)

Needless to say, things get really bad. The Zygons are prepared to kill all the humans. The humans (led by UNIT’s Kate Stewart) are prepared to kill all the Zygons. And it looks like both sides might actually get what they want. Until Twelve locks everyone in a room. Until the Time Lord who has seen far too much war, caused far too much suffering, calls for forgiveness and peace.

Until The Speech.

If you’ve seen the episode, you know the greatness of that scene. It’s a ten-minute master class in passion, conviction, emotion. It’s one of the Doctor’s finest hours. And it might just be the finest moment in Peter Capaldi’s finest performance.

My words will never do it justice, so I’m just going to offer a SPOILER ALERT and let you see The Speech for yourself:

“You’re all the same, you screaming kids, you know that? ‘Look at me, I’m unforgivable!’ Well, here’s the unforeseeable – I forgive you! After all you’ve done… I forgive you.”

I’ve watched The Speech over and over in the last five days, and THAT’S the line where I always well up. It’s one of those moments I love to talk about. One of those moments when Capaldi and The Doctor become one. One of those moments when we’re seeing an actor who believes so fully in his character (in himself) that we no longer see the performance. We see truth.

And that truth is a question. Is Twelve forgiving Bonnie alone… or is he also forgiving himself?

In an already astounding season, this is a scene for the ages. It doesn’t just elevate the episode. It elevates the entire season.

And in this moment, perhaps more than any other, The Doctor proves himself worthy of the name.

With that, I’ll leave you for the next episode. Thanks as always for following along – until next time…