In Molly's comic book world, Fista Puffs is trying to stop a monster at the museum ("The Fistapuffs Theme Song"), however it is a simulation and she somehow is unable to resolve it. Her fellow heroes, Haze and Sha-Boom, are training her to join their team the Pow Pow Boom Booms ("Pow Pow Boom Booms"), but Fista Puffs realizes that Sha-Boom is evil and Haze apologizes for not believing her. Molly, still in comic book form, is called to dinner where her family seems very compliant and tells her to forget her problems ("No One's Home"). Molly realizes that this is wrong and gets called down to dinner for real. Molly reveals that at the museum that day, her friend Hazel began talking to Shauna and was laughing at her jokes. She felt uncomfortable and started making flat jokes. Paige tells an embarrassing story about how she threw up in a friend's mouth while riding a roller coaster to cheer her up, but Molly goes back upstairs disappointed. She resumes the compliant family in her comic, but they all turn on her for hiding her problems and Molly finally confronts them head on ("Trying Too Hard"). Haze and Sha-Boom are back to being Fista Puffs' friends while in the real world, Molly is now hanging out with both Hazel and Shauna ("Pow Pow Boom Booms Reprise").

Owen is nervous because the person he hired to speak for the Central Park field trip had to cancel. Owen refuses to be a speaker himself as he is nervous and recalls getting inspired by another park manager named Ward Whitlinger ("The Answer is Ward"). Paige decides to use her journalism skills to find and locate Ward so that he can speak. Molly and Cole go to see Brendan for his indoor kite flying competition and try to spice up his performance ("Kite String"). Meanwhile, Bitsy has Helen type her memoir, but discovers that her brother Ambrose is typing one too and they race to the publisher. She tells them that they are both terrible, but that Bitsy's is "slightly" better, causing her to gloat, though she later ponders if she is just trying to impress her parents. Brendan gets overwhelmed by the preparation and Molly apologizes as he goes and performs. Ward arrives at the park, but he has lost faith in the earth and gives a cynical speech. Owen, along with Birdie and Elwood take the stage and give an uplifting speech about saving the planet ("Why Bother"). Ward is impressed with Owen's determination and leaves on good terms with him, while Birdie and Elwood suggest making a band with Owen, much to his annoyance ("Why Bother (End Credits)").

With the Tillerman-Hunters not doing anything special today, Birdie takes the audience the time to focus on Bitsy for once; specifically a moment in the past relating to a famous hotel thief called the Shadow ("The Shadow"). The supposed thief strikes again at the Brandenham Hotel. Bitsy, as usual, shows little to no compassion or concern for what has transpired and is further put off when a former officer, now insurance claimer named Hank Zevansky comes with the intent to solve the case. Bitsy is annoyed at Hank's insistence, especially when looking for a "calling card"; forcing Bitsy to confess that she was the Shadow in her youth due to her parents caring very little for her ("That Was All Me"). Hank admits that he knew it was her and had a brief encounter with her in the past ("A Moment Forever Ago"). Satisfied, Hank leaves Bitsy alone who was slightly glad to be noticed. Birdie explains that while it was a small thing, that minor act of kindness meant a lot. In an instrumental segment ("A Thing On Strings (A Busker's Serenade)"), Birdie interacts with an elderly woman and nurse. The woman dies, but Birdie is comforted by the nurse and later by a little boy who dances to his music as he quietly returns to busking ("A Moment Forever Ago (End Credits)").

Birdie explains that the Tillerman-Hunters have had a rough week until Owen was offered a job at Kingsley University in Connecticut. As he mulls the idea over, the family begin to play with building block toys and decide to create their own ideal future should Owen take the job. Molly imagines that she would be a janitor at the University with dreams of being an artist ("Paint the World"), before creating an extraordinary drawing that advances her career in life; her inspiration being Owen. Paige decides to be a successful fiction author ("A Different Paige"), but gets captured by an obsessive fan named Margarett (who resembles Bitsy), only to be saved by a relaxed Owen. Cole takes a spaceship where he befriends an alien, but must return him before the government takes him and is aided by Owen. Owen reveals that he wants to create the perfect park at Kingsley ("Follow Through"), but realizes that no matter where he goes, similar problems are always going to follow him and makes peace with the idea of staying in New York. To his surprise, the rest of the family is happy as they all realize that they cannot leave their favorite things behind and continue playing with the blocks while Birdie sums up the moral ("A Different Paige End Credit").

On a sudden snow day, Birdie loses his violin and his memories in which he cannot tell the story due to the park being in the process of getting sold ("Up to Here"). After Paige publishes her exposé on Mayor Whitebottom, he suddenly announces his resignation; implying that he plans to use the last ounce of his power to sell the park to Bitsy. Bitsy and Helen crash their car in the snow where Helen and Shampagne end up at the Tillerman house. Owen goes out to get Bitsy from the snow where the two argue over their opinion on the park ("Time to Close"). Helen reveals information on the sale to Paige who becomes suspicious. Just as Bitsy and Owen arrive, Paige reveals that the sale is actually going through to Ambrose, Bitsy's brother, who will also own the Brandenham Hotel. Owen realizes that the hotel is Bitsy's "heart" and she becomes empathetic for the first time ("Own It (Reprise)"). Everyone races to Mayor Whitebottom's office to stop the deal with Paige threatening him with exposing more of his duplicitous acts. He cancels the sale, thwarting Ambrose's plans. Bitsy still intends to buy the park someday, Helen admits to Paige that she helped on purpose and Birdie found his violin after his memories are restored; leading everyone to sing together in the now rescued park ("A Walk in the Park").

Abby makes breakfast for Owen and Paige so as to tell them that she got a job at the Brandenham and invites them to dine there for dinner, while Bitsy hires a chef to make a cote de boeuf to be served that evening ("A Positive Light"). Everyone arrives as well as Bitsy's brother Ambrose, his assistant Anton and fiancé Kendra. As the chef is about to prepare the boeuf, Anton states that Ambrose has to have the steak liquified for him. A fight breaks out and the steak disappears. Bitsy immediately blames Abby, but Paige quickly proves her innocence. Soon, everyone begins to accuse one another of stealing the boeuf ("A Real Whodunnit"). Helen figures out that Champagne ate the boeuf and the chef confirms it, but reveals that a steak sauce was added that would have killed Ambrose. Everyone believes Bitsy added the sauce, but Abby thinks otherwise ("Little Good"). They realize that Anton tried to switch the steak, so he could sell it while Kendra added the sauce so that Bitsy would be blamed for killing Ambrose (the two of them were lovers this whole time). Bitsy reluctantly thanks Abby for helping her out while Paige tells her that she is okay with her keeping her job at the Brandenham ("A Positive Light (End Credit)").