David breaks his glasses during a sliding fall down a small hillside, and Susan breaks the heel of her shoe. She walks with a comic hippity-hoppity stride and jokes: "I was born on the side of a hill." David tries to send Susan away. She is tearfully hurt when he rejects her - and she is crushed by his words:

David: ...I want you to go home.
Susan: But...you mean you want me to go home?
David: Yes.
Susan (tears flowing freely): You mean you don't want me to help you anymore?
David: No.
Susan: After all the fun we've had.
David: Yes.
Susan: And after all the things I've done for you.
David: That's what I mean.
Susan: Well all right, I know I have to go when I'm not wanted. And don't you worry about me. I can take care of myself.

As she departs, she stumbles over a large tree branch and disappears out of the frame, crying about how "miserable" she feels that he doesn't like her anymore. He comforts her and dries her tears as she cries: "It's just that everything I do with the best intentions seems to turn out badly." She begs him to reconsider and allow her to rejoin the hunt. They barely avoiding kissing each other before he lifts her up and they begin searching again. She rests her arm on his supportive shoulder:

Susan: Now don't you worry, David. Because if there's anything I can do to help you, just let me know and I'll do it.
David: (cautiously) Don't do it until I let you know.

Following George's barking, they see Baby sitting on a neighbor's roof [for the second time in the film, the two are outside a house at night]. To calm the tame leopard and attract him down off the roof, they serenade Baby with his favorite and fondest song, "I Can't Give You Anything But Love, Baby." The lyrics harmonize with Baby's growls and George's howls (George is held in David's arms). The song becomes David and Susan's anthem of love:

I can't give you anything but love, baby
That's the only thing I've plenty of, baby
Dream awhile, scheme awhile, you're sure to find
Happiness and I guess, all those things you've always pined for
Gee, it's great to see you looking swell, baby
Diamond bracelets Woolworth's never sell, baby
Till that lucky day you know darn well...

The noise attracts the neighbor at the window - it is psychiatrist Dr. Lehman. The doctor diagnoses her as delusionary and hallucinatory after hearing Susan claim: "There's a leopard on your roof." (By this time, Baby has jumped down off the roof.) Believing she's crazy, he finally lures her inside by pointing at an imaginary leopard:

Susan: You don't seem to understand that there's a million dollars at stake.
Doctor: A million dollars?
Susan: Yes.
Doctor (pointing into the house): Well, you will get it. I have it right in there. All in one dollar bills.

The two of them are arrested as dangerous criminals by Constable Slocum and officer Elmer (John Kelly). David is arrested for lurking like a Peeping Tom around the house, and Susan for being crazy (the diagnosis of the psychiatrist).

In adjoining jail cell-cages in the Westlake City Jail, Susan expects to be let out shortly, but David disagrees: "When they find out who you are, they'll pad the cell." The Constable refuses to believe that Susan is Mrs. Random's niece and a phone call to Aunt Elizabeth doesn't provide confirmation: "Of course I have a niece, but she's not singing around under windows. She's decently in bed."

When the Constable questions the prisoners to get at the truth, Susan begins chattering away. David knows that the truth will be hard to get at: "Oh, if you're gonna wait for her to tell the truth, you'll have a long gray beard down to here." Gogarty is hauled into the same jail for returning Dr. Lehman's car that Susan had stolen earlier. At this point, when Mrs. Random and Major Applegate also arrive at the jail to rescue Susan, Applegate stammers to explain his identity: "I'm the niece, er, I'm the aunt, er, I'm Major Horace Applegate." Because the Constable doesn't believe gun-toting Applegate's fantastic story about a leopard hunt, the two of them join the other three already in jail cells.

During David's harsh questioning to get a confession by the doubting Constable, David refers to his criminal associates as "Mickey the Mouse and Donald the Duck." To escape her cell, the always resourceful and creative Susan does a imitation of a gangster's moll (although she pretends to be a manly female) - using a nasal accent and identifying herself as "Swingin' Door Susie":

Susan: Hey, Flatfoot! You ain't gettin' no place. Come here.
Constable: Me?
Susan: Yes you. Come on. Haul it over. Haul it over. You want someone to talk, don't ya?
Constable: Well, it's about time. I certainly do.
Susan: Get me out of this cooler and I'll unbutton my puss and shoot the works.
Constable: Say, hold on, lady...Hey, you ain't no lady.
Susan: Yeah, I kinda had you fooled for a minute, didn't I?
Constable: You sure did.
Susan: I could make a sucker out of a copper. What did I tell ya my name was?
Constable: Why, your name is, uh...Susan Vance. [Vance is a name borrowed from the film The Awful Truth (1937).]
Susan: Vance, Kitty Vance - that's my society moniker. But the mob all calls me Swingin' Door Susie...Now ya pegged me. Come on, Toots. Open up, open up.
Constable: Stop that, stop that. I'm not openin' any doors around here until you promise to talk.
Susan: Listen, I'll talk. I'll talk so much it'll make your hair curl. (She wiggles her fingers at him.)

When the cage door is opened, she literally rides on the swinging cell door to match her name, and waves goodbye to her 'gang.' Then, she strolls up to David's cell and pays tribute, tongue-in-cheek, to a Cary Grant role in another film - The Awful Truth (1937):

Susan: Aw, quit beefin', get wise to yourself, the heat's on, Jerry.
Constable: Jerry? Jerry? Ain't his name Bone?
Susan: Bone. Aww, you mean to say you don't remember Jerry the Nipper?
Constable: Jerry the Nipper. Make a note of that, Doc.
David: Constable. She's making all this up out of motion pictures she's seen.
Susan: Aw, I thought I saw you with that ragged-edged skirt in a motion picture...Sure, I wouldn't be squealin' if he hadn't given me the run-around with that other twist.
Constable: Oh, so he's a lady-killer.
Susan: A lady-killer! Why he's a regular Don Swan. Loves the ladies, don't ya, honey? He bops them over, one, two, three, boom, just like that. He's a wolf.
David: Oh, now I'm a wolf!

After promising to inform on "Jerry the Nipper" and claiming that he is a notorious criminal, she is taken arm-in-arm to the Constable's office. During questioning, she sniffs one of the Constable's cigars: "Oh, it's a two-fer...two fer a nickel." Susan confirms that they are all members of her 'leopard gang,' infamous for robberies and other criminal activities. Sitting on a window sill of an opened window, she manages to escape by driving off in Dr. Lehman's car - stealing his vehicle a second time.

Mr. Alexander Peabody and Alice Swallow arrive at the jail, looking for Mrs. Random and David. [As in most screwball comedies, all the major characters - similar to inmates in an insane asylum - converge for the finale - all but Mrs. Gogarty at the farmhouse.] When it is verified that Peabody is Mrs. Random's attorney, the "old woman" is released. David is also reunited with Alice, but their relationship is finished because he has become too flighty:

David: Well, Alice, it's just one of those things. I can't explain it. It happened and here I am.
Alice: Yes, and in the last place in the world I expected to find you.
David: Well, I don't like it any better than you do.
Alice: Oh really, David.

Although he frees the prisoners, Mr. Peabody and his client Mrs. Random decide to take back the pledge of a one million dollar donation to David's museum:

Mr. Peabody: Huxley, what did you mean by throwing rocks at me last night?
Aunt Elizabeth: What do you mean to tell me - that this is the young man you wanted me to donate a million dollars to for his museum?
Mr. Peabody: Yes, no, no, no, no, I did, but I changed my mind.
Alice: Oh David, what have you done?
David: Just name anything and I've done it.

Two circus officials arrive to report that the dangerous circus leopard they were transporting has disappeared and they are looking for it. The Constable, who has all along denied any of the leopard stories, is now thoroughly discredited and baffled, realizing that every absurd person in his jail has been telling the truth. Suddenly, the tame Baby and George appear in the jail, confirming the leopard's existence. Approaching the purring animal, David adopts Susan's phrase: "Everything's gonna be alright." He shows a fondness for Baby - his familiarity with the tame animal forces one of the circus officials to exclaim: "Hey, wait a minute, that ain't my leopard!" Everyone realizes that there has been confusion - there are two leopards - a fierce, killer leopard, and the Brazilian pet Baby.

David is suddenly concerned for Susan's safety:

Oh, my goodness. Susan's out trying to catch the wrong leopard. Oh, poor darling Susan. She's in danger and she's helpless without me.

Susan reappears outside the jailhouse, determinedly ("I'm just as determined as you are") dragging the angry, spitting wild leopard into the jail (thinking it is Baby) at the end of a rope:

I don't like jail any more than you do...(To David) Well, did I fool you this time? You thought I was doing the wrong thing but I've got him.

But she is dead-wrong this time. When she spots Baby, Susan realizes that the leopard she has on the end of her rope is not Baby, but a real dangerous creature. George and Baby flee into a cell to escape from the killer beast - upsetting all the humans who have already sought refuge there. Screaming and panicking, Susan is saved by David - her commanding hero and animal tamer. Stepping in front of her with a chair, he defends her from the vicious leopard and chases it into an empty jail cell. Susan thanks him for saving her from the leopard she mistook for Baby: "Oh David, oh you're wonderful...You're a hero. You saved my life." Before he can say anything back, he faints into her arms - she catches (and captures) him.

In the film's epilogue, David is back in Brontosaurus Hall in the museum following his wild, frantic experiences. David stands in the Rodin thinker pose next to a shocked Alice (wearing tight black attire). After assessing the situation, she decides to leave David and break their engagement - with an appropriate natural world allusion: "Well, there's nothing else I can say, except that I'm glad that before our marriage, you showed yourself up in your true colors. You're just a butterfly."

After being rejected and puzzling about his future as he sits in the same thoughtful pose, David hears Susan coming into the museum. He fearfully and hurriedly retreats to the presumed safety of the scaffolding erected behind the huge brontosaurus skeleton and scampers up its platform. Susan (in a less rigid black dress) assures him that she has something for him and that "everything's gonna be alright": the intercostal clavicle bone that George had buried. She climbs up a tall, swaying, rickety ladder on the front side of the skeleton (the skeleton is between them) to return the lost bone and to announce that Aunt Elizabeth has decided to give her a million dollars - a sum that she will then donate to the museum:

David: Well, I'm sure they'll be very pleased.
Susan: Aren't you pleased, David?
David: Yes, I suppose so, dear.
Susan: It's too late, isn't it? I made a mess of everything, haven't I?
David: Oh no.
Susan: Oh, I was so happy when I found the bone this morning. Oh David, if I could only make you understand. You see, all that happened, happened, because I was trying to keep you near me, and I just did anything that came into my head. I'm so sorry.
David: Well, I ought to thank you.
Susan: Thank me?
David: Yes.
Susan: Well, why?
David: You see. Well, I've just discovered that was the best day I ever had in my whole life!
Susan: David, you don't mean that.
David: I never had a better time!
Susan: OH! But, but, but I was there.
David: Well, that's what made it so good.
Susan: Oh, did you really have a good time?
David: Yes, I did!
Susan: Oh, that's, but that's wonderful. Do you realize what that means? That means that you must like me a little bit.
David: Susan, it's more than that.
Susan: It is?
David: Yes, I love you, I think.
Susan: Oh, that's wonderful, because I love you too! Stop rocking, David.
David: Oh, I'm not rocking. I-I-I...

David confesses that he has just experienced with her "the best day I ever had in my whole life." Entranced and romantically smitten with his words, Susan's ladder begins to sway wildly back and forth and David imitates her swaying, liberating motion. To prevent herself from falling from the precarious ladder, she jumps onto the dinosaur skeleton and climbs toward him.

Although she has retrieved the missing bone, his entire prized reconstruction (taking four years work) totally crumbles and collapses under her weight just as he gets a hold of her dangling hand to heroically pull her up onto the edge of the scaffolding. She climbs into the safety of his arms from the destruction she has wreaked and humbly asks his forgiveness:

Oh David, look what I've done. Oh, I'm so sorry. Oh, oh, David, can you ever forgive me? You can and you still love me...You do, oh David.

Facing the inevitable, he exclaims during their final kiss and embrace:

Oh, dear. Oh, my. Hmmm.