Choi Mochimazzi, a fortune teller from Dera's homeland, comes to stay at Tamako's house, revealing that both she and Dera come from the island's royal family. When Choi becomes annoyed by Dera gaining weight and forgetting his mission to find a bride for the island's prince, he claims he is being held against his will, leading her to be distrustful of the good will Tamako and the shopkeepers show towards her. As Choi tells fortunes as a mean's of paying back everyone's kindness, shopkeeper Sayuri Yumoto reveals she is getting married, much to the dismay of tofu shop owner Tomio Shimizu, who had a crush on her. This leads Choi to think about her own unrequited feelings for the prince, leading to her getting a fever after passing out in the bath. After Tamako helps her overcome some of her homesickness, she becomes a bit more accepting of everyone's kindness.

Deciding his obesity needs to be addressed, Tamako, Choi and the others decide to put Dera on a mochi-free diet until he loses enough weight to fit into a birdhouse Kanna made. In order to keep watch over Dera to make sure noone feeds him, Choi goes to school with Tamako and the others, where she joins in on classes and helps Dera get some much needed exercise, before going to a used clothes store. As Dera shows up the next day with a curiously slim body, Kanna and Midori give Choi a sweater they made for her.

As word spreads about Tamako allegedly being a princess, Tamako herself is more focused on collecting enough loyalty points to receive a medal from the shopping district. After Tamako earns her medal, Choi manages to fix Dera's communication features and get in contact with the prince, Mechya, who exchanges some words with Tamako before Dera breaks down again. Whilst Tamako herself feels she's not really a princess, the neighbourhood have a meeting concerning Tamako, feeling she should probably go, although Tamako herself feels otherwise. The next morning, Tamako panics when she can't find her medal, only to be given it by Mechya himself.