In drama class, the teacher is asking the students to perform a scene. Violetta volunteers Mia for the main role, setting up for a romantic scene with a kiss between Mia and Vincent. The two decide to try to perform it, even though neither of them have kissed anyone before, while Violetta decides to arrange for all the students to be present during the performance, all for the purpose of embarrasing them. When Mia's bracelet begins to glow while the two are rehearsing the scene and she has to leave, the teacher asks Violetta to step in when Violetta makes a snide remark about Mia.
Arriving in Centopia, Mia finds herself landing near a spot where some of the other elves are in the middle of practicing their water bubble shots. Yuko and Mo suggest that Mia give it a try too, with Mo lending Mia his water shooter. Mia tells them the newest riddle, with Yuko and Mo making a guess as to which area the riddle refers to.
Elsewhere, on an island nearby, a snake-like creature known as Polytheus expresses his annoyance with the noise the elves are making, but he changes his tune once he moves in close to investigate and overhears Mia, Yuko and Mo discussing the riddle, specifically the part alluding to a treasure. Polytheus decides to follow them in hopes of finding treasure.
While flying through the forest, the group spots the unicorn herd of the forest. Gargona and the dark elves fly overhead, but the unicorns manage to avoid their detection. Mia and the others continue moving forward, only to find themselves lost in a forest full of living plants. Polytheus spots them and decides to move closer, only to get grabbed by some vines. Mia hears him calling for help, and Yuko and Mo tell her about Polytheus.
Going to assist Polytheus, the snake-like being immediately takes an interest in Onchao. Polytheus introduces himself as a travelling merchant, and as he asks about Onchao, another plant tries to attack him, but Mia manages to push it back with the water shooter. Polytheus expresses his gratitude, and claims to be in the area to look for a potential location to open up a new shop. Seeing that the elves aren't sure where to go, Polytheus informs them he has a map of the area, and offers to help on the condition that they each get to keep the treasures they find. Yuko and Mo are skeptical, but admit that he might be their best option for finding out where to go.
Polytheus joins the heroes and reach the right area, and Onchao manages to locate the entrance to the cave. Mia, Onchao and Polytheus enter the cave, while Yuko and Mo stay outside to keep look-out. While Mia suggests to Polytheus that they stick together, he quickly disappears down one path to look for treasure. Onchao tells Mia to head down the other way, and they eventually spot some cave paintings depicting winged unicorns, and pick up a piece of something shiny, albeit not a trumptus piece. Meanwhile, Polytheus finds a golden unicorn statue, that he picks up.
A cave-in traps Mia and Onchao behind a wall of rocks. Mia asks Polytheus to help, but he is initially hesitant to help, until Mia claims there is more treasure on her side of the wall and reminds him that he owes her a favor after she saved him earlier. Polytheus is able to save them, but has to sacrifice the statue he found. He initially wants to head back in deeper to look for more treasure, but agrees to leave with her when the cave continues to crumble. In the process, Mia finds and picks up the trumptus piece.
After making it out of the cave, Polytheus expresses his displeasure at not obtaining any treasure, and initially expresses interest in Onchao again, but then notices Mia's pouch and pulls out the trumptus piece and the golden piece of something else Mia found earlier. He dismisses the trumptus piece as worthless, and takes the other item instead. After Polytheus leaves, Onchao restores the trumptus piece and the group head back to the castle to return it. Mia remembers her drama class, and returns to her own world.
Back in school, Vincent is nervously reciting his lines as he and Violetta share an awkward moment on stage, but luckily for them, the class ends just before they get to the kiss. Relieved, Vincent comments that his first kiss will have to wait, while Mia begins telling him about her latest adventure.
- Man-Eating Plant: One of these tries to eat Polytheus.