1. Muromi-san on the Brink

Takuro Mukojima is outside fishing when he reels up a girl who introduces herself as Muromi-san, a mermaid.

2. Muromi-san and the Legendary Sea Creatures

Muromi-san gives Takuro her cellphone number and is upset when he doesn't send any messages despite her sending him hundreds. Later, Takuro fishes up another mermaid who introduces herself as Levia-san (Leviathan), a giant sea monster from the Old Testament.

3. Muromi-san and Old Memories

Levia-san, Hii-chan, and Sumida-san try to get Muromi-san to get over her hatred of marine mammals. She hates them because she had a boyfriend in the Mesozoic era who had developed lungs, but decided to stay in the ocean anyway. She thinks whales and dolphins are his descendants. Levia-san tells Muromi-san that that toothed whales returned to sea after having evolved into complete land mammals, which means her ex-boyfriend either evolved into something else or became extinct.

5. Muromi-san and Twin Mountains

Fuji use to admire Muromi and her gorgeous tail, but the current status of Muromi tail only brings anger.

6. Muromi-san and Ryuuguujou

After catching an unemployed fish, Muromi tells Takkun about the Ryuuguujou and the evil Otohime.

7. The Boy, Kappa and Muromi-san

While river fishing, Taku can’t escape the salt water Muromi or her legendary friends.

8. Muromi-san and the Nice(?) Type

Trapped by a gang of deadly sea animals, Muromi has only one chance of survival.

9. Muromi-san and the Secret Advanced Civilization

Youthful pride of Curiosity, how far will Taku go to learn more about the ancient civilizations that tried to defy the gods?

10. Muromi-san Worldwide

Ciel gets the chance to meet a unique cast of characters and later Yeti has to call on Takku for help.

11. Muromi-san and the Heatwave

Otohime has taken up multiple jobs like selling popsicles. She tells Tak-kun why she hates mermaids and her fall from the top. She tried to take what was left of her money and take a crack crack at the stock market, but that all fell through. It seems that her feud with Muromi is the result of a misunderstanding that is not easily cleared up. The two actually have nothing against one another. Takkun tries to help them out, but things don’t go too well on that front. A night of drinking together with Levia-san may have helped, but we may never know...

12. Muromi-san and Different Forms of Love

Fuji turns to the one person who might help her convince Muromi to regrow her tail fins.

13. The Years go by Muromi-san

Muromi is preparing a new years joke while Tak-kun is worried about his future. Muromi gives him some advice and in return, Tak-kun presents her with a present. Muromi then goes to enjoy the hot springs and watch the first sun rise of the new year with everyone.