As Mia is teaching Sara more about Centopia, someone shows up at the door. Sara quickly sends him away, explaining to Mia about how the people from his company show up once a year to ask about buying their property. However, it turns out Luciana has an appointment with the man. The man asks to see the flower field, and Sara worries her mother might be planning to sell it. Mia observes the two, but can't tell what they're discussing from the distance. As the two come back, they overhear the two talking about doing business. After the man leaves, Luciana explains that they're selling the field. Sara doesn't want to sell, but Luciana thinks it is necessary. Mia wants to go after her, but Luciana tells Mia it might be best to give Sara some time alone. Mia's bracelet then begins to glow.
Mia travels to Centopia, where she discovers that parts of the fields where the unicorns live at are becoming covered in thorny vines. With the vines getting closer to the crater, the elves must find the rest of the heart crystals. Mia tells the group about the riddle, and Yuko suspects that her sister might know something, so the elves decide to pay Kuki a visit.
Kuki tells the elves about a very shy unicorn said to live in a certain swamp. Mo also wonders about who the "lying girl" mentioned in the riddle might refer to. Not having enough information to work with, Mo suggests they just begin searching for the unicorn. However, as they approach the swamp, they're approached by a girl who accuses him of bothering the animals. Mia tries to explain the situation, but the girl claims she's no familiar with the swamp, and leaves to bring a frog she found back home. Noticing several signs that the girl has been in the swamp, the group reach the conclusion that the girl must be who the riddle refers to.
The elves follow the girl, who introduces herself as Lola. Lola has no interest in helping the elves. Mo tries to explain that they need her help to defend Centopia, but Lola is still unwilling. However, as the elves refuse to leave, she agrees to at least lead them to the flowers associated with the unicorn. Lola and Mo continue to bicker as they head through the swamp, but Mia thinks Lola might simply be protective of the swamp because it is all she has, and that she has been keeping to herself for too long.
Lola eventually manages to slip away from the rest of the group, and meets up with the unicorn. Separated from the others, Mia tries to use her butterfly to find her friends, before spotting Lola talking to the unicorn. Lola wonders why the unicorn still won't let her pet her. The other elves accidentally scare the unicorn away, much to Lola's annoyance. Yuko offers Lola her friendship ring so she can call on the other elves in case something happens, and as Mo muses that he messed everything up, Mia wonders if Lola might be lying to herself as well.
By herself, Lola discovers that the unicorn has gotten stuck and is sinking. Unable to pull her up, Lola wonders if she should use the ring to summon the other elves, or if doing so would make things worse. However, with no time to waste, she decides to call on Mia.
Mia and the others arrive and try to save the unicorn, but aren't strong enough to pull her out. Mo thinks of a plan to use a nearby tree to help pull the unicorn out, and Lola helps them get the tree down to the unicorn so they can pull her out. Mia tells Lola that the unicorn is grateful that she summoned her friends to help her, and that she'll let Lola pet her. As Lola embraces the unicorn, she finds a heart crystal hidden in her mane. Lola entrusts the shard to Mo, telling him she'll trust him and the other unicorn guardians to protect Centopia. She tries to return the ring, but Yuko insists that she keep it. Lola finally accepts the elves as her friends, before Mia has to return home.
Mia returns to find Sara calling for her, and admits that she wants to talk to her mother. Sara admits to Luciana that she wants to return to her old school, but finds it difficult to do so, although she thinks she might be able to do it with Mia's help. After talking for a bit, Luciana calls the man from earlier and tells him that she has changed her mind, choosing to believe in Sara and Mia.
