During the dramatic revelation scene in the beach house, in a lengthy monologue, Maxim recounts how his marriage with Rebecca was a "rotten fraud." Far from being the wonderful and beautiful person held so dear and worshipped by Mrs. Danvers and the other servants, Rebecca's character was vicious, conniving, and cruel. As a cuckolding creature, she mocked her husband with infidelity. She also told him "all about herself - everything. Things I'll never tell a living soul." [Speculation: Did she tell him that she was bisexual? Had she conducted an affair with Mrs. Danvers that was strongly hinted at earlier?] Rebecca was unfaithful to him, and married him only for his money. He remained married to her only to protect the "family honor." Only four days after their marriage on their honeymoon, she made a "dirty bargain" with Mr. de Winter:

Maxim: Do you remember that cliff where you first saw me in Monte Carlo?...That was where I found out about her...She stood there laughing, her black hair blowing in the wind and told me all about herself - everything. Things I'll never tell a living soul. I wanted to kill her. It would have been so easy. Remember the precipice. I frightened you, didn't I? You thought I was mad. Perhaps I was. Perhaps I am mad. It wouldn't make for sanity would it, living with the devil. 'I'll make a bargain with you,' she said. 'You'd look rather foolish trying to divorce me now after four days of marriage. So I'll play the part of a devoted wife, mistress of your precious Manderley. I'll make it the most famous showplace in England if you like. Then, people will visit us and envy us, and say we're the luckiest, happiest, couple in the country. What a grand show it will be! What a triumph!' I should never have accepted her dirty bargain but I did. I was younger then and tremendously conscious of the family honor. Family honor. She knew that I'd sacrifice everything rather than stand up in a divorce court and give her away - admit that our marriage was a rotten fraud. You despise me don't you, as I despise myself. You can't understand what my feelings were, can you?
Mrs. de Winter: Of course I can, darling, of course I can.
Maxim: Well, I kept the bargain and so did she, apparently. Oh, she played the game brilliantly.

Maxim also describes how Rebecca became careless and promiscuous, especially with a man named Favell:

Maxim: But after a while, she began to grow careless. She took a flat in London and she'd stay away for days at a time. Then, she started to bring her friends down here. I warned her but she shrugged her shoulders. 'What's it got to do with you?' she said. She even started on Frank, poor faithful Frank. Then there was a cousin of hers, a man named Favell.
Mrs. de Winter: Yes, I know him. He came the day you went to London.
Maxim: Why didn't you tell me?
Mrs. de Winter: I didn't like to. I thought it would remind you of Rebecca.
Maxim: Remind me, as if I needed reminding.

He recounts the troubling event of the night of Rebecca's death for his second wife. Maxim begins by describing how Favell would often visit Rebecca at the beach cottage. One night, the night of her death, Maxim decided to confront her:

Favell used to visit her here in this cottage. I found out about it and I warned her that if he came here again I'd shoot them both. One night, when I'd found that she'd come quietly back from London, I thought that Favell was with her. And I knew then, that I couldn't stand this life of filth and deceit any longer. I decided to come down here and have it out with both of them. But she was alone. She was expecting Favell but he hadn't come.

[During his story-telling and re-enactment, the camera pans through the room, pausing on various key objects (such as the divan and the ship's tackle coiled up on the floor) and following Rebecca's actions while he reconstructs them. A 'ghostly' Rebecca has indeed come back from the dead as Mrs. Danvers had once suggested.]

She had attempted to have her husband murder her by telling him that she was pregnant with another man's child. By laughingly goading him and suggesting that the other man was possibly her own cousin, playboy Jack Favell, she drove him half mad by implying that another man would inherit his family's entire estate. During the fearsome taunting and quarrelling, Rebecca accidentally tripped over some ship's tackle on the floor, fell, and struck her head - and was mortally wounded:

She was lying on the divan, a large tray of cigarette stubs beside her. She looked ill, queer. Suddenly she got up, started to walk toward me. 'When I have a child,' she said, 'neither you nor anyone else could ever prove it wasn't yours. You'd like to have an heir, wouldn't you, Max, for your precious Manderley?' Then she started to laugh. 'How funny! How supremely, wonderfully funny! I've been a perfect mother just as I've been the perfect wife! No one will ever know. Now, it ought to give you the thrill of your life, Max, to watch my son grow bigger day by day and to know that when you die, Manderley will be his.' She was face to face with me. One hand in her pocket, the other holding a cigarette. She was smiling: 'Well Max. What are you going to do about it? Aren't you going to kill me?' I suppose I went mad for a moment. I must have struck her. She stood staring at me. She looked almost triumphant. Then she started toward me again, smiling. Suddenly she stumbled and fell. When I looked down, ages afterwards it seemed, she was lying on the floor. She'd struck her head on a heavy piece of ship's tackle. I remember wondering why she was still smiling. Then I realized she was dead.

[In the novel, de Winter is goaded into killing Rebecca, but in the film, she is accidentally killed - although it is still possible that de Winter could have killed her and then covered up the murder. Censors of the era always required that a murderer had to receive punishment, so the film avoided this resolution.]

After the long re-enactment, Mrs. de Winter reacts: "But you didn't kill her. It was an accident!" Maxim finishes the story of how he panicked and then covered up the act. He took Rebecca's body to her boat, went into the ocean and deliberately sank it by making a hole in its hull, and then escaped and watched it sink. Afterwards, he lied - claiming that Rebecca was lost in a storm at sea and drowned:

Who would believe me? I lost my head. I just knew I had to do something, anything. I carried her out to the boat. It was very dark. There was no moon. I put her in the cabin. When the boat seemed a safe distance from the shore, I took a spike and drove it again and again through the planking of the hull. I'd opened up the sea cocks and the water began to come in fast. I climbed over into the dinghy and pulled away. I saw the boat heel over and sink. I pulled back into the cove. It started raining.

And then when a body conveniently washed up at Edgecoombe, he identified it as the body of his late wife. The revelations emboldens Mrs. de Winter to take control, and she suggests an alibi for him. He should simply claim that he was so distressed about his wife's death that he made a mistake about the identity of the body at Edgecoombe that had washed up some distance away - and hide the truth about why he had lied:

Mrs. de Winter: Maxim, does anyone else know this?
Maxim: No, no one except you and me.
Mrs. de Winter: We must explain it. It's got to be the body of someone you've never seen before.
Maxim: No, they're bound to know her. Her rings, bracelets she always wore. They'll identify her body. Then, they'll remember the other woman - the other woman buried in the crypt.
Mrs. de Winter: If they found out it was Rebecca, you will simply say you made a mistake about the other body, that the day you went to Edgecoombe, you were ill, you didn't know what you were doing. Rebecca's dead. That's what we've got to remember. Rebecca's dead. She can't speak. She can't bear witness. She can't harm you anymore. We're the only two people in the world that know Maxim, you and I.
Maxim: I told you once that I'd done a very selfish thing in marrying you. I can understand now what I meant. I've loved you, my darling. I shall always love you. But I've known all along that Rebecca would win in the end.
Mrs. de Winter: (hugging him) No, no. She hasn't won. No matter what happens now, she hasn't won.

The telephone rings. Frank calls to inform him that the Chief Constable of the county, Col. Julyan (C. Aubrey Smith) has been asked by the police to go to the mortuary. He wonders whether Maxim might have made a mistake about the other body. At a preliminary meeting, Maxim admits his mistake about the body. But there must be another inquest following an inspection of the boat that has been disgorged by the ocean. Mrs. de Winter instructs the staff at Manderley that all newspapers should be kept away from her husband.

At Manderely the night before the coroner's inquest, Mrs. de Winter is worried about how her husband might lose his temper at the hearing, and lovingly asks to be there at his side, as they stand in front of the huge fireplace: "I must be near you so that no matter what happens, we won't be separated for a moment." Maxim notices how his new wife has lost her youth and matured in spite of his wishes, and they share a very mature, heart-felt embrace and some kisses after he confesses to her:

I can't forget what it's done to you. I've been thinking of nothing else since it happened. It's gone forever, that funny young, lost look I loved won't ever come back. I killed that when I told you about Rebecca. It's gone. In a few hours, you've grown so much older.

At the inquest, one of the witnesses, a boat builder, confirms that Mrs. de Winter was an expert "born sailor." He also reveals that the boat was "scuttled" intentionally from the inside. The drain valves in the bottom of the boat were deliberately opened to flood it and that's what sank the vessel. There were also holes in the planking that appeared to have been made from the inside, although they may have been the result of the boat's submergence for over a year. It is suggested and speculated, but then dismissed, that Rebecca de Winter may have deliberately committed suicide. Mr. de Winter is also called to testify and asked about the holes in the boat, Rebecca's possible motive for suicide, and about the state of his marriage to her:

However painful it may be, I have to ask you a very personal question. Were relations between you and the late Mrs. de Winter perfectly happy?

Under the strain of the inquest, Maxim becomes agitated and yells angrily. He is about to divulge the truth: "I won't stand this any longer and you might as well know now..." but his testimony is disrupted by Mrs. de Winter who fearfully faints to the ground in the front row. Maxim assists his wife and escorts her to their car.

During an adjournment until after lunch, the conniving Jack Favell invites himself into their car, helps himself to a drumstick (part of their lunch), and then questions the holes made from the inside on the planking of the boat in which Rebecca was placed - he alludes to "foul play" and murder. Attempting to implicate Maxim in Rebecca's murder, he produces as blackmail a note written by Rebecca to him the day of her death. The note arranged for their meeting at the beach house - Favell insists that Rebecca was not suicidal:

I can assure you that it is not the note of a woman who intends to drown herself that same night.

Then, he blandly associates the piece of chicken he has been eating with Rebecca's mysterious death: "By the way, what do you do with old bones?" In another veiled attempt at blackmail, he asks: "I'd like to have your advice on how to live comfortably without hard work." Favell and the de Winters leave the car and enter into a private room in the town's inn for the remainder of the lunch period. During a conversation, Favell tells Colonel Julyan: "I only want to see justice done, Colonel," after Maxim accuses him of withholding the note as a "vital piece of evidence" - for purposes of blackmail. He reads aloud Rebecca's last note to him to prove that she was not suicidal (and that she was his lover):

Jack, darling. I've just seen the doctor and I'm going down to Manderley right away. I shall be at the cottage all this evening, and shall leave the door open for you. I have something terribly important to tell you. Rebecca.

Favell suggests that her note implies a suspicion of murder - not suicide, but he lacks witnesses or a motive for murder.

To provide a possible motive - "the missing link" - Favell asks Mrs. Danvers to present evidence against Maxim. She defensively shields Rebecca and is uncooperative, but she is forced to admit that Rebecca was clever and manipulative. She would often amuse herself and laugh at men because "love was a game to her, only a game." At the mention of Rebecca's possible deliberate murder by Mr. de Winter, Mrs. Danvers blurts out the name of Rebecca's doctor - the one she visited in London on the day of her death: "Dr. Baker." Inadvertently helping to clear Maxim, Favell insists that her visit to the doctor was related to Max's motive for murder - Rebecca provoked her husband to strike her down after revealing to him news of a child:

Go and question Dr. Baker. He'll tell you why Rebecca went to him, to confirm the fact that she was going to have a child, a sweet, curly-headed little child...She told Max about it. Maxim knew he wasn't the father, so like the gentleman of the old school that he is, he killed her.

Following Favell's allegations, he and Maxim take Colonel Julyan to Dr. Baker's (Leo G. Carroll) office and inquire about the record of Rebecca's visit the day of her death. She was not registered as de Winter but used an assumed name: "Danvers." The real motive for Rebecca's death is explained, clearing up whether it was murder or suicide. On the day of her death, she had learned that she was NOT pregnant with a child but suffering from terminal, inoperable cancer. She knew that she had little time left before her death. Dr. Baker reveals Rebecca's last words in the office - she was determined to end her life immediately to spare herself from a long and unglamorous death:

When I told her it was a matter of months, she said, 'Oh no doctor, not that long.'

Rebecca had wanted to provoke Maxim into killing her in the beach house (taunting him with the deceitful news of a pregnancy by another man and carrying a child that would someday inherit his possessions) to try to destroy him as well. Proving unsuccessful in that attempt, she had stumbled and accidentally killed herself in the beach house. This explanation provides a believable motive for her suicidal fall. Maxim is exonerated of any wrong-doing and the inquest is terminated. But he is upset all over again while remembering how Rebecca taunted him (and 'laughed' at him) the night of her death.

In the film's eerie and suspenseful conclusion, Favell calls Mrs. Danvers from a phone booth to tell her that her deceased mistress Rebecca had kept the truth from both of them ("Rebecca held out on both of us - she had cancer"). The housekeeper is surprised when she realizes that now "Maxim and that dear little bride of his will be able to stay on at Manderley and live happily ever after." [Hitchcock's cameo appearance: he walks behind Favell as he speaks to a policeman about his illegally-parked car following the call.] Crazed by the truth that is revealed about Rebecca, Mrs. Danvers carries a lighted candle through the darkened hallways and sets Manderley on fire, determined to burn the cavernous mansion. As Maxim drives home from London and proceeds up the long driveway to Manderley, the sky is brightly lit by the flames of the mansion. He exclaims: "That's not the Northern lights. That's Manderley!"

Outside after finding each other and embracing, while they watch the great house burn behind them, Mrs. de Winter tells her husband:

It's Mrs. Danvers. She's gone mad. She said she'd rather destroy Manderley than see us happy here.

Mrs. Danvers is consumed in the blazing inferno as the flames burn her and the memories of her mistress. The faithful housekeeper is last seen through a West Wing window, remaining trapped inside Rebecca's bedroom with the memories of her beloved. The spirit of Maxim's first wife is at last excised from Manderley and the couple resolve to build a happier life. The flames move through Rebecca's bedroom, consuming her bed and then her monogrammed pillowcase with an embroidered R on it.

[Note: The final image of the film is very similar to the image of the burning of the sled Rosebud (a symbol of the past) in the following year's Citizen Kane (1941).]