(gentle music) (water splashing) - I think the whole season has been about fathers.

It's a season about fathers.

Good fathers, bad fathers, indifferent fathers, and murderous fathers, they are all there.

- My big story is that I find out that Michael's my dad.

This whole series has been building up to this scene so it was quite an important moment for Morgan.

I knew it had gone good when my heart was beating fast at the end of the scene.

- [Annika] So when- - Is Michael my dad?

- Yes.

Yes, he is.

- Michael's had time to let it percolate.

- We had a celebration dinner last night, Jake came.

- Okay.

- And she asked if you were her dad.

- How is she?

- [Annika] Letting it sink in.

- I know that Michael's my dad, and then it's like my mum and my dad are coming to save me, and there's lots of things going on.

- There's a brilliant tiny flash of Morgan, Annika and Michael as a rather strange but functioning family unit.

You know, they're never going to be a normal family unit, but you definitely get the feeling that there is a good relationship.

And then of course you have Annika returning to the station, maybe thinking she can breathe a little bit because her daughter is safe.

She's being looked after by Jake, there seems to be some, you know, calmer waters with her and Michael, Gary Nair is probably the one we're looking for, and then the bombshell is Gary Nair is nothing to do with the murder and it's her father.

So suddenly, this sort of moment of, you think you're getting one ending and then that just gets thrown up in the air.

I didn't know that my father was going to be the murderer.

I thought Nick was bringing my father into the story because it would be really interesting to see how she responds to him.

You know, this unloving father.

I thought, oh, that's great, Nick's examining...

He's always looking at family relationships I think, how we interact with the people that we love.

And so I was very surprised when I suddenly picked up that, oh no, he's come back for something else.

He's come back to, yeah, to cover his tracks from something he did years and years ago when he came to Scotland.

- Help me.

- It's you that she looks to and asks for help as her world completely tilts.

I think it's a great end of it.

- And cut.

- Got it.

- [Director] Great.