Every Inside No. 9 Twist Ranked
4. Thinking Out Loud - They're All Split Personalities
Plot: This episode consists of various characters monologing to the camera and recording video messages - they are all somehow connected.
Eventually, it turns out that the various different characters are all split personalities inside the head of Nadia (Maxine Peake).
The only character who isn't inside her head is Bill (Phil Davies), who appears doing a video for an internet dating site at the start of the episode. He's her father and when he beat Nadia's mother to death, she was so traumatized that she started to develop dissociative identity disorder.
At the end of the episode, she takes on the personality of an American murderer (Pemberton) and kills her father in revenge for what he did to her mother all those years ago.
It's a complicated reveal but it's absolutely brilliantly done. Not only does this make for a seriously powerful and thought-provoking ending that'll linger with you for a long, long time to come, but the dialogue is the reveal scene is very smart and Peake does a superb job of acting as the different personalities.
As well as this, it all adds up very well since the episode is full of subtle clues of what's really going on and everything is wrapped coherently at the end. It's a truly masterful ending all around and one of the best and most interesting depictions of split personalities you'll ever see.