I was wondering why Diane was styled after the red room, and why Dale's superimposed head suddenly appeared on screen when he saw her, when suddenly it all fell into place: Dale has been held prisoner for 25 years.... He is now a Mancurian Candidate brainwashed over 25 years by the Black Lodge spirits so he will unwittingly reveal where the Fireman is hiding Laura. I know it sounds insane, but actually it's no less insane some of what is in The Secret History book, and basically if you follow it through the idea fits every scene, and also matches the police procedural/conspiracy tone that Twin Peaks has always had.

In the Sheriff's office, Dale turns around to look at Naido, she twitches a little, then basically the image splits in two - the real and the dreamed. The superimposed head is the real Dale looking at Naido, maintaining the exact confused expression he has at the moment he sees her. He is frozen in a waking dream, and the events in the Sheriff's Office start to unfold literally inside his head. (This is bit goofy, but when you watch it again, at the moment the image splits, freeze your body and head as motionless as you can, and keep your eyes open as long as you can, and you will actually experience the scene much in the same way that Dale must be experiencing it! It is like an out-of-body experience.)

I am not sure if it is a) Dale standing completely still, frozen while the dream plays out in his head; or b) the Sheriff's Office scenes are all real, but Dale is simply no longer in control of his own body: his mind is trapped inside of himself, watching things unfold without his control. If it is the latter, then perhaps this is how Leland feels when BOB surfaces and takes control of his body. This is maybe even how Dale felt while he was trapped inside Dougie - when he woke up in the hospital it was strongly suggested that his mind had been present watching everything as it unfolded, he was a passenger inside his own body, watching things move without his control. I actually wonder if Lynch and Frost had talked about what it must feel like to be Dale inside Dougie, and kind of as a treat for the viewers, right at the end of the season decide to show us what it is like to be in this state. Anyway, the next big piece of evidence...

The clock! Now Dale is in a trance, Red Room Diane can reveal herself and take stronger control over him. The sequence in which she transforms, and her funky red room styling afterwards, strongly suggest that she is connected with the red room. I assume she is a red room spirit, or maybe even a personification of the room itself. (I don't know for sure but we may even find out somewhere down the line that she is Judy, who knows!). I noticed that during Diane's transformation, when the red room appears the head disappears for a moment, and we focus on the weird rock floating around, that opens and reveals Diane's head inside. It's really hypnotic, I wonder if this symbol is also a brainwashing trigger to begin completely taking over Dale's mind? Anyway...

Notice that when Diane kisses Dale, the head disappears again and for a few seconds Cooper seems to be returned to himself - locked in the kiss with an evil spirit he now knows is controlling him. Perhaps this is like the moments when BOB gave Leland back control of his own mind - the kind of nasty bullying you would expect an evil spirit to play on it's host. 

Dale turns around and looks at the clock and suddenly the superimposed head is back. He is no longer in control. What does the clock say - we are stuck in 2:53! Time has frozen. This is a clue to suggest scenario A from above, and Dale is standing, frozen still on spot while this dream is playing out in his head. Then the floating head tells us exactly what is going on: "We live inside a dream". You can't really put it much simpler than that.

Then we have this weird moment where it fades to black, spooky sounds play and Dale and Cole shout to each other. We are given a few seconds of the head by itself, trapped in the dream. Then the head fades out.

This is the point where I think Dale loses conscious of what is happening to him. I think his true character is completely suppressed at this point much in the same way we will see Laura suppressed in Carrie. He has been taken over full-on Mancurian Candidate style. His behaviour from here on out even reminds me of how the Liev Schrieber character acts in that remake. If you watch the scenes with that in mind, Dales sudden sluggish behaviour completely makes sense. He is happily carrying out tasks and going through the motions, but he never seems completely aware of what he is doing, never completely aware that he is being manipulated by the lodge spirits. Notice Cole looks a bit puzzled and even suspicious during this sequence. After reading Secret History, which talks a lot about how evil spirits inhabit bodies to control events on earth, and thinking about how the brainwashing behind Mancurian Candidate must be totally up Mark Frost's street - it totally makes sense that having this happen to Dale is a major plot point.

We now hear the tibetan bowl humming sound that we heard when Cooper woke up in hospital and spoke to Mike. And who should appear, but Mike himself! Cooper is back with the evil spirits again. Mike reads the FWWM poem to Coop completely like the way in which triggers are used to activate people Mancurian Candidate style. From this point until the end of the forest sequence, Mike completely acts like Cooper's handler. Keep an eye on Mike during the Jefferies sequence - if you watch carefully you can see he looks completely shifty the whole way through, worried the ruse might fail, until finally he knows the plan is working and then he screams "electricity" in success!

I think the information Jefferies reveals is just a gimmick to aid in stringing Cooper along, with no real meaning to it, it even starts off as an owl symbol - the symbol of the Black Lodge! People have been wondering how Jefferies has the power to send people through time, I am not sure that he does at all. I think this is all just for show. Jefferies of course is also a Lodge Spirit being controlled by them manipulated into doing what they want him to do. I think when we hear the electric noises at the end of this sequence and focus on Cooper's face while we fade to black, Cooper is not time traveling at all but rather the Lodge spirits are putting him in a simulation or a hallucination, another dream, using clips from FWWM and the pilot episode no less!  I think this also explains why Jumping Man is on the staircase earlier - of course he is there, this is where evil spirits come to hang out! There are probably a few of them around.

Basically the whole sequence is a scheme to trick Cooper into thinking he had a chance to save Laura, but he failed and now she is gone. In the simulation they make it seem like Cooper saves her and everything is rosy and it all flips into colour - then BOOM! She is taken away. Cooper has failed big time. He must feel completely responsible for it. Notice that as soon as Laura has disappeared, Cooper turns his head and suddenly he is back in the Lodge with Mike smiling at him. I think he has never really been out of the spirits domain since entering the 315 door. 

It is not revealed when or how, but at some point the evil spirits learned that the real Laura was hidden somewhere, and the Fireman gave Cooper directions on how to find her. In fact, during the Fireman's conversation, the Fireman says "It is in our house now. It cannot all be said aloud" like he is giving the directions to find Laura in code, because he knows they are being watched. The evil spirits know that only Cooper can figure out this code, which is why they need to trick him into taking them right to Laura. 

Next the arm reminds Cooper "Is it the story of the little girl who lived down the lane? Is it?" I am guessing this is just another cute and cryptic Lynchian way to make sure Cooper keeps thinking on track about saving Laura and what has just happened. Immediately after this we get a shot where the Laura tulpa whispers in Coopers ear (probably something along the lines of "You did this to me!" or "Please come and find the real me!") and disappears again. Look at the shame, the guilt and responsibility on Cooper's face as she disappears. Finally we see Leland again who says specifically: "Find Laura!"

The trick has worked - Cooper is now set his mind on tracking down Laura. He leaves the lodge and meets Diane, a lodge spirit. Using the Fireman's first clue, they ride to the portal at 430 miles. I am not sure, but I think maybe the motel is like a connection point between all the time zones or alternate realities. You enter from one door, and leave the door to another time point/dimension. I am not sure. Some people have said that Diane and Cooper have sex as a kind of ritual that triggers the opening in the dimensions. That may be true. It may be that you need two real humans to perform this ritual and what we actually see her is the real Diane, who is also a prisoner and being forced to do things by the evil spirits. In the car she keeps asking Dale if he really wants to keep on with the mission, like she wants him to change his mind but she can't say it directly because she is being monitored.  Maybe this Diane herself is Mancurian Candidated-out, and she is acting beyond her wishes but part of her deep within still sense what is going on - when she makes love is it like when Bob let Leland have brief glimpses of what he was doing. 

Anyway, whatever it is - ritual or not, Diane is no longer needed so she disappears. I am thinking that from this point, in Odessa, Cooper is left to track down Laura while the evil spirits lie hiding elsewhere. I think they can't monitor him closely, or the Fireman will sense it, so they just lay low trusting Cooper is on the right course. All he has to do is find Laura and bring her back out into the open so the evil spirits can find her. This would explain the Diane Tulpa (maybe the spirit from the Sheriff's office earlier) watching them from the hotel, and also who is following them in the car later.

Following the Fireman's clues, Dale tracks down where Laura is hidden. I think Richard & Linda is simply an intuitive note to point him in the right way. I think seeing the diner marked "Judy" is also a partial intuitive clue for him - remember the negative entity does not actually have a name, "Judy" is the word the FBI use to refer to her, based on the old human expression Jao Dei. Even Mr.C who seemed to know of the Judy entity did not seem to know of this codeword for her. Anyway, this leads him into the diner, where he gets the address from the waitress. (I wondered if this was the "2 birds, 1 stone" clue, because Dale looks at the waitress and in his head seems to work out that there is a second waitress, which is true and he gets the address for her house - 2 birds, 1 stone - 2 waitresses, 1 address. It makes sense that the final clue in the set of three is similarly connected to finding Laura. Why Cooper also said this phrase earlier to Cole is anyones guess - but maybe it's just another red herring in the main narrative like we got for both the 430 clue and the Richard And Linda clue - that now makes 1 red herring in the main narrative for each clue.)

Finally he gets to Carries house. I think this might be the Fireman's Safehouse because there is a final #6 electric pole outside. The Fireman showed this to Andy in Andy's vision, and it is almost like a final marker for Dale (and also us the audience who saw Andy's vision) to know that he is in the right place.

Inside - I am not sure what is up with Carrie and the dead body. I can't help think that it is just Lynch and Frost's twisted humor to show how well hidden Laura is that her host body Carrie is a bit of a dubious character! There is no real info revealed to us either way. They do make a point to show us the white horse though, that seems to suggest Carrie really is a Palmer girl. Maybe this is her true spirit, taken out of her and kept on the shelf? (Like others I assume that Sarah was either possessed, or whatever was dormant inside her woke up, during the sequence where she watches the animals on TV, immediately following the monster in the box - so there is no reason to assume she was evil before that in season 2 when she had the horse visions). 

Dale, perhaps expecting Laura, but not Carrie is confused and decides to take her back home to safety and her mother. Remember Dale also has no knowledge of what has happened to Sarah, so he thinks this is ok. When Dale mentions Sarah's name Carrie reacts like she seems to recognise it. This seems to be the beginning of her recollection, as later in the car she hazily starts reminiscing about her youth. I notice that as they enter Twin Peaks they show an extended shot of a modernised gas station, followed shortly by the Double R, closed at night. I was wondering if these are visual clues to signal that we are in the future - Ed and Norma have happily retired from work to spend time with each other. The diner is still there, perhaps a "Norma's franchise", but Big Ed's Gas Farm has been bought and modernized. Also, having the Palmer house passed down through a few owners strongly suggests that Sarah has left and time has moved on.

Dale and Carrie arrive at the house. By this point, Sarah Palmer has left the house, and care of it has been passed onto the evil spirits the Chalfonts, and now the Tremonds. I am wondering if Alice Tremond is a front, and she is being controlled by the voice behind the door. I think the reason they are using the real house-owner is just a fun kindness to pay back for allowing them to use the house again. The family are now known to be huge Twin Peaks fans. It wouldn't be the first time that has happened in a film. Also, maybe the voice behind the door is the Tremond Grandson grown up! One thing to notice is that when Dale asks if she knows who owned the house before the Chalfonts, Alice says "No but... (talks with the voice, then replies strongly)... NO." Like she was going to say something but was warned not too.

Finally Dale and Carrie go into the street. Now I think one of either two thing happen - a) The Chalfonts work out what has just happened and call up the other evil spirits, possibly Diane, or maybe Judy, to say "She's here!" Then the spirits come out, call "Laura!" and Laura wakes up. Or b) After being triggered by Dale earlier, when looking at the house Laura slowly resurfaces. As she does the evil spirits sense her and immediately show up calling "Laura!" Laura screams.

Either way, as Cooper is no longer needed at this point maybe his memory is vaguely coming back too, or maybe just through his own strength he is slowly starting to fight through it triggered by all the confusion and wake up on his own accord. Whatever the case, it seems that Dale has performed his duty by revealing Laura, so he is no longer needed and starts to come out of it himself.

I expect the lights in the house blowing out is just for creepy dramatic effect, and this is a cliffhanger if they wish to make a season 4 or not.

There we have it: Twin Peaks: The Return of both Dale Cooper and Laura Palmer in the final scene. Aka Twin Peaks: Dale Is A Black Lodge Mancurian Candidate. If you watch the whole sequence again assuming this, it just fits every scene. It may even be that this was the plan right from the very start of the season - and Dale had been programmed and ready to be triggered the whole time he was Dougie. He was in the lodge for 25 years after all so plenty time to plan it and carry out the brainwashing. The end purpose was always to reveal where the real Laura was, as the Lodge spirits discovered when they murded a Laura Tulpa and found they had been tricked.   

I suspect that this storyline was mainly Mark Frost's, and maybe Lynch played with it to make it more ambiguous, allowing for multiple interpretations from the abstract Mulholand Drive "Dale is Richard" type ending, to the meta-commentary "you can't get back the past" ending.

One point which you have probably noticed: when Sarah smashes the picture. This is the only cutaway scene from the Sherriff's office until the end of the show where we are not also with Dale. Maybe it is just a metaphorical shot to symbolise to Dale that he has "won" some how, even though he is not aware of Sarah being inhabited. Maybe it is just a red herring shot for the viewer. Maybe Judy is an enemy of the Black Lodge too. Maybe they fear her too. Who knows?