The  movie starts with Dom Cobb (Leonardo) washed up to a beach, he is   injured and delirious. He opens his eyes once and sees two kids playing   on the beach. Some men with guns take him to an old man telling him Cobb   is alone with a revolver and a brass top. The old man tells Cobb, he   had once known a man who had that top with him and his name was Cobb.
The   scene shifts to Cobb, Arthur (Joseph Gordon-Levitt) and Saito (Ken   Watanabe) having a quite dinner, while Cobb is explaining him that if   Saito wants to protect himself from Extraction (stealing an idea from   dream) he would have to let Cobb in to his mind. Tell him all his   secrets. Saito seems uncertain and a little suspicious and leaves the   room saying he will consider the proposal. Cobb and Arthur move out of   the room and Arthur says Saito suspects something is wrong. Cobb says   'All the secrets are in that room. He looked right at it when i said   safe'. Arthur then points out a woman in the crowd to Cobb and asks   'what is she doing here?'. Cobb then goes to meet her and he calls her   'Mal'.
Next scene we see Mal and Cobb in a room, Cobb  makes Mal  sit on a chair and ties a rope to the leg and ties to climb  out of the  window down the building. We get to know from their  conversation both  know each other very well. Cobb climbs into the same  room where he was  previously having dinner and opens a safe and takes  an yellow envolope.  Just then Saito and Mal enter the room with guns.  Cobb asks Saito if Mal  told him the truth. Siato says 'what truth? that  we are all in a  dream?' Then we see Cobb, Arthur and Saito actually  sleeping in a room  and a fourth guy monitoring them. Out side the house  they are sleeping  in, mobs are creating a riot and getting closer.
Back  to the  dream, Mal brings in Arthur and shoots him in the leg, because  killing  someone in the dreams will only wake them up, but pain is part  of the  brain and its the same in real or deam world. Cobb shoots Arthur  in the  head and kills him, and Arthur wakes up in the house. In the  dream, all  hell breaks lose, fighting and gunshots and buildings  crumbling, Cobb  tries to read the papers in the envolope.
In  the sleep house  Arthur tells the monitor to wake up Cobb, who pushes  Cobb into a bath  full of water. With amazing dream visuals of water  breaking through  walls and entering into dream in sync with the real  world bath water,  Cobb wakes up, and so does Saito. There is a struggle  between all, and  Cobb says Saito dint put all the secrets in the safe  and he needs them  for the men who hired him, he threatens to kill him.  Saito then realizes  even this is a dream and it is the 4th guy's. As  the rioting mob from  out side breaks into the house all 4 of them wake  up in a train. Cobb  and Arthur and the dream architech leave the train.  Saito wakes up alone  with a teenage kid in his compartment.
Next  scene we realize,  Cobb has been running from US authorities and he has  two kids and they  are with their grandmother. Cobb and Arthur decide  to lie low for a  while thinking their employer would not be very please  about the botched  job. Saito catches up with them with his men and  offers a proposal.
He  wants Cobb to carry out  Inception (putting an idea successfully into  someones mind). If he did,  then he can go back home to his kids and  Saito will make sure all  charges against him are dropped. Cobb agrees to  this in desperation  knowing it is an extremely complicated process.
To   assemble the dream team he goes to meet his father who is a professor   in an university and asks for a good architech. His father introduces him   to Ariadne (Ellen Page) saying she is better than him. Cobb then takes   her into a dream and makes her realize in dream you can design your   world. She starts building the world as she goes walking in the dream.   Cobb then explain all the nuances of designing a dream, that you can   allow someone else's subconcious into your dream and thats why Cobb is   there, and all the people around him are his projections or shades,   where as the dream world itself is designed by Ariadne.
As  she  keeps changing the worlds he warns her that too much of change  warns the  subconcious that its not real but a dream, and people in the  dream  start staring at her. She creates a bridge out of memory, which  Cobb  recollects as one of the places at which he spent time with Mal,  he  worriedly tells her creating something exactly like a memory brings  out  the sides of subconcious that we wont like. Suddenly everyone grabs  them  and Mal walks up to Ariadne and stabs her. Both Cobb and Ariadne  wake up  in a workhouse, she freaks out completely and leaves. Cobb  tells Arthur  that she will be back and he goes to get a forger  (imitator) and with  Saitos help brings Eames (Tom Hardy ) and Yusuf  (Dileep Rao) into the  team. Yusuf tells them about a sedative which is  used for complicated  layered dream.
The team decides  to do a three layered dream set,  with the third layer being the crucial  point where the idea will be  planted. The target is Robert Fischer,  Jr., a multimillion dollor oil  company heir, with his father dying he  is ready to take over completely.  His god father is Browning a key part  of the empire. Saito wants Cobb  to plant an idea in Fishers head to  ruin his own empire.
While  prepping for the job  Ariadne learns that Mal is Cobbs deseased wife and  actually sees a bit  of his past while in his dream one day. He has  issues that are making  him uanble to architech any dream without  bringing in Mal as a spoiler.  Ariadne warns him he should tell others.  Cobb tells her that, this is  why he is avoiding knowing the architecture  of the dream so he doesnt  know the secrets.
Arthur explains to  Ariadne about  totems, something which tells a person whether he is in a  dream of real  life. Cobb has a small brass top ( same as the one we see  in the  beginning of the movie), Arthur has a loaded dice. Arthur  explains that  in a dream a spinning top would never stop. Ariadne sets  to build a  totem for herself.
When Fisher Sr. dies, they decide   to execute the plan on a plane to LA in which Fisher Jr. is carrying his   fathers coffin. Saito books the entire flight, and Cobb slips Fisher   the sedative. 10 hours of real world gives 1 week in the first level   dream, 6 months in the second level and 10 years in third level dream.   Their wake up call is the free fall which brings them out of dreams.
They   enter the first level of dream. It is raining heavily. Arthur, Saito   and Eames kidnap Fisher and take him to a warehouse. They get ambushed   on the way by gunmen, and Cobb explains that Fisher might have been   trained against dream extraction and these are his defenses. Cobb's   subconcious brings a frieght train right in the middles of the road.   They some how reach the warehouse but Saito gets hit. When Arthur tries   to kill him, Cobb stops him saying the sedative they all took will not   allow them to just wake up. If you die before the sedative wears off  you  just go into a limbo, a middle world which could mean eternity to a   mind stuck in there. By the time you wake up your mind is scrambled  and  you lose yourself.
When Ariadne confronts him  about being the  cause of the train in the middle of the road, he  confesses that he cant  seem to get Mal out of his dream. He tells her  the story how she died.  During their last dream together, something  goes wrong and they get  stuck in a limbo. Cobb tries to convince Mal  that this isnt real and  they should go back. They spend 50 years in the  limbo when finally she  agrees to come back. But when they did, Mal  keeps thinking they are  still in dream and that dying is the only way  to wake up. She calls Cobb  to a hotel room on their anniversary and  tells him she sent a letter to  their attorney saying Cobb is trying to  kill her. She says she did that  so it would be easy for him to die. She  jumps off the balcony and with  cops chasing him Cobb flees the  country.
Eames impersonates  Browning and screams like  he is being tortured. Arthur and Cobb talk to  Fisher wearing masks.  They tell him there is a safe in his office and  they want code to that.  Fisher denies knowing any safe, when he hears  Browning's screams he  asks them to let him speak to him. Eames  impersonating Browning, tells  him his father wrote a second will  dissolving the empire and he, Fisher  can use it if he wants to. Fisher  wonders why he would want to  dissolve his empire, Browning says may be  his father wanted him to  build his own, and that he loved him. Fisher  says his father dint love  him coz his last words to him were that he was  disappointed.
Fisher's  defenses start closing in on the  warehouse. They decide to do the  second level dream in a van. Yusuf is  there to drive the van and he should  drive it off the bridge. That free fall is  their trigger to come back  from dream. They enter second dream sequence  architectured by Ariadne  and Arthur. It is a restaurant in a hotel  where Cobb meets Fisher as  his security officer. He makes him realize  its a dream because he  doesnt remember how he ended up there and the  gravity keeps shifting  (Deam stage 1 Fisher's defenses are chasing and  trying to destroy the  van). Fisher's own mind projects Browning in the  dream as the bad guy  who is behind the kidnap, the projection Browing  confesses saying  Fisher empire is all he ever worked for and he couldnt  let him destroy  it with the will in the safe.
Cobb convinces  Fisher  that he should enter a dream and know browning's secrets. They  all  gather in a room and enter third level.
Third level of  dream  is set in snowy mountains, where the safe is in a house guarded  heavily  by armed men. Cobb tells Fisher to go to the house and open the  safe.  Eames and the rest draw the guards away.
Dream  state 1: van  drives off the bridge. 10 seconds left state 2: No gravity  situation.Floating. Arthur is getting everyone  together. 3 mins left  state 3: Fisher is struggling to get to the safe. 60 mins left
After   a long struggle, Fisher finally reaches the safe. But just then Mal   appears, when Cobb hesitates to shoot her , she shoots Fisher killing   him. Cobb then shoots Mal. Everybody gathers around Fisher. Even Saito   dies. Ariadne proposes they go in deeper and get Fisher out. He must  be  in Cobb's limbo as Mal is nothing but a projection of his mind.
Ariadne   and Cobb enter 4th level dream. The world in which Mal and Cobb were   stuck for 50 years. They go to the house and find Mal sitting in the   kitchen. Mal accuses him of leaving her telling him he promised they   would grow old together. She tells him he is confused and the place they   are in is the real world. He should stay there. Cobb tells Mal that  she  isnt real and Cobb has been guilty a long while. The brass top is   actually Mal's.
Jumping to flash back when they were  stuck in  limbo Mal locked the top away in a safe. Cobb found it one day  and put  the idea in her mind that that was not a real world. He left  the top  spinning in the safe. When the idea became a strong belief. Mal  agrees to  leave the world, they both lie on the train track to die and  wake up in  their house. But the idea takes possession of her mind and  she dies  thinking she would wake up. And thats how Cobb knows inception  is  possible.
In the kitchen Cobb tells Mal, this is  not real and  that he is going back.
Dream state 4:  Cobb tells Ariadne he will  have to find Saito.Ariadne finds Fisher and  pushes him off the cliff.  and falls down herself. state3: Eames  defibrillates Fisher who wakes up and goes into the safe.  finds his  father there, who gives him the will from the safe beside the  bed.  (This is Fisher's own dream). Ariadne wakes up state2: Arthur has pulled  everyone into lift and creates a free fall  situation with explosives.  Dream state1: Van is about to hit the water
Van  hits the  water. everyone wakes up and swims up the river.
Back  to the  first scene. The old man talking to Cobb, we realize its Saito.  Cobb  tells him he should come back, Saito takes the gun in his hand.  Next  scene, Cobb is waking up in the plane and so is Saito. He makes a  call.  After deboarding the plane Cobb gets past immigration without any   problems. His father comes to pick him up and takes him to his old  house  where he again sees his kids playing out in the backyard.
Cobb   spins the top on the table to see if this is real, just then the kids   see him and run to him. He goes to hug them and the camera focuses on   the top spinning, and just when we are about to see if it is going to   stop the screen fades black. 

(Forwarded)