"When Uniqua pokes her finger on a thorn, she becomes Garden City's newest superhero, Flower Girl, dedicated to keeping things rosy and defeating Gloom Meister (Austin)."
Uniqua is in the backyard holding a basket of flowers. She introduces herself to the viewer as Flower Seller Uniqua, a florist. She sings "Things Are Always Rosy" as she explains her job. The backyard transforms into a large city known as Garden City. Uniqua happily gives Window Washer Tyrone and Trolley Driver Tasha some flowers.Then she notices that she ran out of flowers, so she says that she'll go to Gardner Pablo's greenhouse to restock.
After they exchange greetings, Pablo offers her to look at the many new flowers that he got recently, while he refills her basket with all of her favorites. After admiring some flowers, Uniqua notices a strange bud that is shut. After coming to the conclusion that it needs more sunlight she carries it to the window. The bud opens as soon as it is put in the window, and is revealed to be a beautiful flower. At this time Pablo comes over, bringing her basket with him. As he comments about it's beauty, he tells her that he never saw the bud in bloom before. Uniqua attempts to pick the flower to smell it, but is pricked by it's thorns. As a reply to Pablo's concerns about her, she tells him that she got pricked, and not to worry since that happens to her all the time, escpecially since she spends most of her time with flowers.
Pablo agree's with her and hands over the basket as he turns around to head back to work. Suddenly a patch of flowers shoot from Uniqua's hand and lands right behind him. He turns around in surprise and asks her how she did that. Uniqua herself is surprised as she tells him that she doesn't know. Then from her hand fireworks start shooting above them. The third time a cloud of pollen springs forth and leads to plenty of sneezing and couging from Pablo, who got hit. Uniqua asks what is going on with her, to which Pablo replies that the strange flower that she touched probably has given her flower powers. He scoops a spadeful of dirt and tells her, that basically she's a big, walking, talking flower. Afterwards, he drops the dirt on her head. Then, he says that flowers need water and sprays some from a spray bottle on her. Uniqua begins to float. And the most important of all, he told her is sunlight, and he opens a window. Uniqua states that she feels the power, and as she floates higher and higher she finally hits her head and comes tumbling down. She gives an exasperated sigh and wonders how she'll be able to do her job like she is now.
Pablo calms her down by saying that she just needs to practice her powers, and Pablo and Uniqua sing "Superhero Practice" as Uniqua practices her flower powers. At the end she finally is able to control her powers, and she transforms into a new outfit. Before leaving she tells Pablo that she's not just a flower seller, that she's also Flower Girl, the superhero in Garden City. She flies out to make Garden City beautiful with flowers. Meanwhile, Trolley Driver Tasha and Window Washer Tyrone see Flower Girl flying towards them. They start arguing if it's a bird or a plane, but Uniqua flies over and introduces herself as "Flower Girl!". Then she begins decorating the town in flowers.
Everybody is happy and amazed. Meanwhile, in a corner of the city, Austin, who is pretending to be the evil Gloom Meister, is plotting his plan to destroy Flower Girl and her flowers. He shoots a ray of shadows at Trolley Driver Tasha, causing her to drive down the street. But Flower Girl heard her yelling for help and so she rushes to her. Tasha closes her eyes as she's about to drive off the harbor, because she couldn't see where she was driving, but Flower Girl shoots flowers into the ocean and Tasha lands softly on them. As soon as Trolly Driver Tasha's warm thanks reach Uniqua she hears another cry of help, and she rushes to the buildings, where the sound came from. It turns out that the Gloom Meister shot some shadows on the flower grown building, where Window Washer Tyrone was working at. Tyrone cannot see where he is washing and falls. Flower Girl makes it just in time to make a giant flower to cushion his fall.
Flower Girl tries to find the evildoer who is causing the residents harm, and sees Gloom Meister return to his underground lair in the sewer. Flower Girl blasts the manhole lid open, and flies after him. As she tries to get her surroundings she gets caught in a booby trap cage. Flower Girl tries to use her powers to get out, but they do not work. Then Gloom Meister comes out of his hiding spot and tells Flower Girl that she can't breack his cage because he made it flower proof: no dirt, no water and no sunlight.
The Gloom Meister introduces himself to her laughs maniacally and Flower Girl asks if it is his true laugh. The Gloom Meister answers no, and adds that he only does it to look scary, and shows her his real laugh: a combination of giggles and snorts. Flower Girl agrees that the first laugh was better. The Gloom Meister and Flower Girl sings "Me and My Shadows". He presents Flower Girl with his Gloomsday Machine saying that he will make the whole City dark and gloomy, and laughs his actual laugh again. He "corrects" himself by laughing the other way. He presses a button, and part of the ceiling slides open. Sunlight comes out of the opening. The Gloom Meister uses the machine to shoot shadows through the opening all over Garden City. Then he stands on a rising platform, takes his Gloomsday Machine outside to cover more of the city, and leaves Uniqua in the cell.
While Flower Girl is in the cage, the platform descend back, allowing some sunlight to come through the opening in the ceiling. Since her powers work with sunlight, she barely reaches some of it, and then uses her power to get out of the cage. She grows a giant sunflower and climbs it out of the sewer. Meanwhile, all three citizens reach the last bit of light and plead for Flower Girl to help them. Flower Girl comes and destroys all the shadows with her colerful beams. Instead of being sad, the Gloom Meister begins singing "This Is My Song" as they argue and start battling with their powers. The citizens are watching, hoping that Flower Girl will win the battle.
The Gloom Meister catches her off gaurd and uses the opening to shoot a shadow from his Gloomsday Machine on her, causing her to gasp and shudder. Uniqua doesn't give up, telling the Gloom Meister that he forgot about to disable one power, that is not dependent on sunlight, dirt or water. Instead, she asks the Gloom Meister to say "sneeze". And shoots a full blast of pollen right at him. As he stumbles around blindly, all the while sneezing to get the pollen away, he accidentally turns off his machine by bumping into it. Uniqua, being freed, destroys the device by covering it with flowers.
The citizens ask Gloom Meister why he did not like flowers, and he sadly answers that he is scared of them. They tell him not to be afraid and show him how good they smell. He changes his feelings and now loves flowers. Then Austin redubs his character, Gloom Meister, into the Bloom Meister. He asks to be Flower Girl's sidekick, and Flower Girl accepts and invites them all over to her house for sunflower seeds to save Tyrone's growling tummy.
The city transforms back into the backyard and they sing the end song. They rush to Uniqua's house and shut the door, only to open it again and shout "Flower power!"