Tired and ready to sleep for the rest of the day, Morgan isn't allowed to rest - Slim follows him into his room and advertises her availability:

Steve: What do you want?
Slim: I could use a match. (He tosses her a box of matches.) Thanks. Now I need a cigarette. (He silently points to his supply and wearily sits down to remove his shoes. She offers to help.) Here, I can do that...Oh come on, let me help.
Steve: Look, when I get ready to take my shoes off, I'll take 'em off myself.
Slim: Alright. Want something to eat?
Steve: No.
Slim: Just a little breakfast?
Steve: All I want to do is get some sleep.
Slim: It's a good idea. I could help you there.
Steve: Hey, now where are ya goin'?
Slim: I'm gonna fix you a nice hot bath. It'll make you sleep better.
Steve: Look, Junior, I don't want you to take my shoes off, I don't want you to get me any breakfast, I don't want you to draw me a nice hot bath. I don't want you to..
Slim: Isn't there anything I can do, Steve?
Steve: Yes, get the...
Slim: You know, Mr. Morgan, you don't make me angry when you say that. (mockingly) I don't think I'll ever be angry again at anything you say. (She flutters her eyes at him) How am I doin', Steve? Does it work the second time?
Steve: You've been wantin' to do somethin' for me, haven't ya?...(She agrees)...Walk around me. Go ahead, walk around me. Clear around. (He gestures for her to circle around him, and she obeys.) Did you find anything?
Slim: No. No, Steve. There are no strings tied to you - not yet. (He grabs her to show her the door - then they stop and passionately kiss each other. She reacts with a purring voice.) I like that, except for the beard. Why don't you shave (she strokes his stubble and lightly and playfully slaps him) and we'll try it again.

Their heated encounter is interrupted - Captain Renard is plying Eddie with rum in the hotel cafe to get information from him, and Morgan must leave to extricate his besotted buddy from the authorities:

Steve: It's a good thing you didn't get me in that tub.
Slim: Look out for those strings, Steve. You're liable to trip and break your neck.
Frenchie: Strings? I didn't see any strings.
Slim: They just don't show, Frenchie.

The Vichy police suspect that Morgan was up to something amiss when he admits to being confronted by the patrol boat while fishing late at night with Eddie: "Does a professional fisherman go fishing for his own amusement?" Renard directly blackmails Morgan to betray De Bursac and dangles the promise of paying him $500 plus the $825 that was confiscated:

What about your two passengers?...You could have landed them a dozen places on our coastline...Would five hundred dollars refresh your memory?...Would your memory become any better if your passport and money were returned to you?...Think it over and let me hear from you.

That evening in the downstairs bar, the scene opens with Cricket at the piano playing a bluesy song about "a poor unfortunate colored man who got arrested down in old Hong Kong." The lyrics describe a man in a foreign land far away from home ("the land of the free" in Frisco) who wishes to return home to find happiness once again:

Well, they say his home's in Frisco where they send the rice
But it's really in Tennessee
That's why he say: 'I need someone to love me
Need somebody to carry me home to San Francisco and bury my body there.
Oh, I need someone to lend me a fifty dollar bill and then I'll leave Hong Kong far behind me for happiness once again
Won't someone believe I've a yen to see that Bay again
But when I tried to leave, sweet local man won't let me fly away.

Slim wears a silky black taffeta dress (with a bare midriff) as she's "goin' to work" as a singer in the cafe. To deliberately get a rise out of her, Morgan admires her provocative dress:

You won't have to sing much in that outfit.

Although Eddie was warned to stay away from the police, he has once again disappeared and Morgan is worried that he has been detained by police. He playfully jokes with her further about her slinky outfit:

Cricket: Stick around for a while, she's gonna sing.
Morgan: I'll be right back.
Slim: Give her my love.
Morgan: I'd give her my own if she had that on.

He visits the recovering patient De Bursac in the cellar, and is relieved that the patriotic freedom fighter has almost been restored to full health. Morgan has made up his mind, however, to leave Martinique ("Frenchie, I'm pullin' out") as soon as he finds Eddie, and he suggests finding an alternative hiding place for De Bursac after he departs:

De Bursac: Would it be best if we went with you, Captain?
Morgan: Why do you want to go? I'm still tryin' to get out of the jam I got into bringin' you here. Just why'd you come here in the first place? (He gestures toward Helene.) I know why she came, she told me, but why did you?
De Bursac: Did you ever hear of Pierre Velmar?
Morgan: Pierre Velmar. Yeah. Read a headline. He was quite a guy. Vichy got him. He's dead, isn't he?
De Bursac: No, no, no. He's on Devil's Island. They sent me here to get him, to bring him back here to Martinique. He's a man whom people who are persecuted and oppressed will believe in and follow.
Morgan: Just how are you gonna get him away?
De Bursac: You don't think much of me, Captain Morgan. You're wondering why they have chosen me for this mission. I wonder too. As you know, I'm not a brave man. On the contrary, I'm always frightened. I wish I could borrow your nature for a while, Captain. When you meet danger, you never think of anything except how you will circumvent it. The word 'failure' does not even exist for you, while I - I think always 'suppose I fail' and then I'm frightened.
Morgan: Yeah, I can easily see how it wouldn't take much courage to get a notorious patriot off Devil's Island, but uh, just for professional reasons, I'd like to know how you're gonna do it.
De Bursac: We will find a way. It might fail, and if it does, and I'm-I'm still alive, I will try to pass on my information, my mission, to someone else. Perhaps to a better man who does not fail, because there's always someone else. That is the mistake the Germans always make with people they try to destroy. There will be always someone else...Originally, we planned to do everything from here, but then because of my own clumsiness, it was impossible. And that's the reason we have to go with you.
Morgan: Well, I couldn't even get you on the dock. They've got a man down there watching. There's one upstairs. They're all over the place. How would I get you through the streets?
De Bursac: How will you go?
Morgan: They're watching me to find you. As long as I haven't got you along, I can at least get on the boat. There'll be a fog again, and the tide will turn a little after midnight. I can cut loose and drift out beyond the breakwater before I start my engines. I'll still have trouble enough even without you...
De Bursac: Captain Morgan is right. This is not his fight, yet. Someday I hope, it may be because we could use him. You have done enough for us already. Gerard told me of your refusing Renard's offer to give us up.
Morgan: How do you know I won't do it yet?
De Bursac: There are many things a man will do, but betrayal for a price is not one of yours.

Upstairs in the cafe, Morgan informs Slim that he is leaving with Eddie - and she is to join them for a midnight departure: "We're leaving here for good - the three of us." He predicts rough-going for a while, but she is eager to conquer any obstacles with him:

Steve: It'll be rough, I'm broke. If we do get out of here, it'll be with a couple of hundred gallons of gas and a few francs, just about enough to get us to Port de Prince, maybe.
Slim: I've never been there.
Steve: I don't know when you'll get back home. Could be a long time.
Slim: Could be forever. Are you afraid of that? I'm hard to get, Steve. All you have to do is ask me.
Steve: How long will it take ya to pack?

Slim happily sings "How Little We Know" in a deep voice (with Cricket at the keyboards), a song that expresses the transitory, uncertain and shifting nature of life - similar to the changes that will soon be affecting her own romantic future:

Maybe it happens this way, maybe we really belong together
But after all, how little we know
Maybe it's just for a day, love is as changeable as the weather
And after all, how little we know...
Maybe you're meant to be mine, maybe I'm only supposed
To stay in your arms awhile as others have done
Is this what I've waited for - Am I the one?
Oh, I hope in my heart that it's so
In spite of how little we know.

Meanwhile as he makes plans to leave, Mme. De Bursac makes an impassioned plea to Morgan in his upstairs room to take her valuable family jewelry with him: "I want you to take them out of here with you and save 'em..." She must hide in the bathroom when alerted by Slim that Captain Renard is on his way up. The Gestapo leader appears at the door with two bodyguards, still searching for the underground leaders he ferried with his boat. Eddie is being held for questioning by them and tormented to the breaking point by being denied liquor: "If you will not give us the information we want, perhaps he will. Before we make the mistake of giving him liquor, this time we will withhold it." Morgan's anger is quickly aroused - incensed that Eddie has become a victimized pawn of the Vichy Gestapo: "You know what that will do to him...he couldn't stand it, he'd crack up."

By an unspoken understanding with Slim (regarding cigarettes and matches again) in this final, tense showdown scene, Morgan directs her to open a drawer (where his gun is kept) to fetch some cigarettes and matches:

You got a cigarette?...You'll find some in that drawer, Slim.

She tosses him the cigarettes and leaves the drawer open. He craftily moves over to the table, frisks himself and mumbles: "I haven't got a match," and grabs for the concealed gun in the open drawer. Without drawing it up, he fires it through the furniture and kills one of Renard's silent henchmen. He threatens and taunts the others after turning the tables around:

Go on, pull your guns. Go ahead. Go ahead, get 'em out. (He overturns the table) Go ahead and try it. You're gonna get it anyway...You've been pushin' me around long enough. So you were gonna drive Eddie nuts, pickin' on a poor ol' rummy that never...slappin' girls around. That's right, go for it. Your boy needs company. (His hand is shaking, so he shifts the gun to his steadier left hand.) Look at that! (He glances at his trembling hand.) Ain't that silly? That's how close you came.

The remaining two policemen are disarmed and handcuffed, and Renard is coerced by Morgan into telephoning for Eddie's release: "You're both gonna take a beating 'til someone uses that phone. That means one of you's gonna take a beating for nothin'. I don't care which one it is." He pistol-whips Renard to secure Eddie's release and safe passage for them and his boat.

As Slim packs, Eddie is freed and returns to the hotel, and the De Bursacs prepare to leave on Morgan's boat. Renard is also made to fill out harbor passes for everyone. After he turns the police over to the Gaullists, Morgan even proposes to fulfill De Bursac's mission by taking them to Devil's Island to rescue another freedom fighter. Frenchie wants to know why Harry has ultimately decided to help the Free French:

Frenchie: Why are you doing this, Harry?
Morgan: Well, I don't know. Maybe 'cause I like you, maybe 'cause I don't like them.
Frenchie: I'm glad you're on our side, Harry. (Frenchie gratefully begins to hug Morgan)
Morgan: (joking) No kissin', Frenchie.

As they hurriedly pack, Slim echoes the familiar question of Morgan's deluded partner to refresh his alcohol-starved memory:

Slim: Was you ever bit by a dead bee?
Eddie: Was you?
Slim: Yeah. You know, you gotta be careful of dead bees. They can sting ya just as bad as live ones, especially if they was kinda mad when they got killed.
Eddie: I feel like I was talkin' to myself.
Slim: I bet I've been bit a hundred times that way.
Eddie: Why don't ya bite 'em back?
Slim: I would, only I haven't got a stinger.
Eddie: Oh, I remember you. You're all right. She can come, Harry. It's OK with me. Now I'll have the two of you to take care of, won't I?

The three proceed through the smoky bar to the dock, with just enough time for Slim to say goodbye to piano-playing Cricket:

Slim: Cricket, I came to say goodbye.
Cricket: What?
Slim: We're leaving now. Thanks for everything.
Cricket: Hey Slim. Are you still happy?
Slim: What do you think?

He begins playing "How Little We Know" - reprised in a faster, upbeat mode - it irresistibly prompts Slim to shimmy/samba her hips on the way out of the hotel - Eddie is brought in tow from behind - jerking, limping and carrying a pair of their suitcase luggage. The film ends and fades out on the final note of the song.