Get ready for a wild and sexy ride unlike anything you’ve ever experienced before, as beautiful sisters Ai, Mai, Mii, their android maid Mea and slippery pet ferret Unagi, make an amazing journey together through time and space without ever leaving their beloved mansion behind! Following the clues of the strange dandelion-like “Popotan,” the girls are theoretically seeking the person who has the answers to their most personal questions, but they seem to have more than enough time to take side trips, meet new friends, visit hot springs and occasionally operate the Xmas shop they keep in the house along the way! Yet, the girls’ ultimate destiny holds more than a few surprises of its own, and not every moment is filled with hilarity, as moving through time means having to leave friends behind as well. Tears of laughter, sadness and joy punctuate one of the most temporally unique adventures ever animated in POPOTAN!
Daichi has found himself in a tough situation: his school mate told everyone that they believe in ghosts & now they need proof. To save his friend's reputation, Daichi goes to what he thinks in a haunted mansion to get pictures of real ghosts, but instead finds himself face-to-face with a real naked girl! Ai, Mai, and Mii are touched by Daichi's devotion to his friend and agree to help him stage some ghost pictures to show everyone at school.
Since the sisters move from place to place, they have to say a lot of goodbyes. This has become very hard for Mai, so when they arrive in a new town, she is determined to not get attached to anyone. Of course, she can't control the fact that someone else has already become attached to her.
Mii's favorite TV show and obsession is about a magical girl named Lilo, who helps people. Ai takes her into town to buy a magical costume and Mii runs around, offering assistance to everyone she sees. One such person is a father whose daughter is in the hospital. When Mii learns that she does not have any friends and is fan of Lilo, she pays her a visit. The two become close friends and their antics cause all kinds of chaos throughout the hospital.
Mea is tending the mansion's Christmas Goods Store when a sweet young girl comes in. Mea tries to convince her that it is not a toy store. The girl mentions that she is from the nearby village and then vanishes when the others come home. Mea, at first annoyed by the girl, becomes curious when Ai tells her that the village has been abandoned for years.
The sisters travel to a hot spring resort. Soon, Ai meets a Popotan that may have clues for where they can find what they are looking for. There is a catch, however. The Popotan will only tell them if they all participate in all of the activities the resort offers.
Ai and Mii become separated in time and space from Mai and Mea. When they travel back to their last location, they realize that they arrived five years in the future from when they had left. Ai and Mii have to explore the hot spring resort and town to find if Mai and Mea are still there, or where they might be.
The sisters head to the beach, arriving near a popular resort. Almost immediately, Ai runs into Daichi, the boy they helped with the ghost photos, only now he's all grown up. Ai is spared from having to try to explain the fact that she has not aged by a mysterious stranger. The man steps in and covers for Ai, so that Daichi thinks he's mistaken her for someone else.
The girls' next stop is an old village, where they park the mansion next door to a Shinto priest. The priest's grand-daughter, Nono, is intrigued with the mansion and falls in love with the Christmas store. Her grandfather, however, is very strict and is less than welcoming to his new neighbors.
Mai, who has always had a hard time saying goodbye, thinks she has been given a second chance, when she sees her best friend, Konami. It turns out the the girl is not Konami, but rather her daughter. Mai tries her best to befriend the girl.
As more clues and hints are discovered, the sisters believe that they may be close to finding what they have been looking for. Mea also is finding new things when she remembers how she once worked for some brothers before joining the Popotan sisters.
The girls have reached the end of their journey and are ready for answers. At Shizuku's place, they are given a choice: stay together, or continue in their travels.
The girls have departed each others' company and live their own lives. It is a bittersweet decision for all.