Mukoujima Takurou is a lonely teenager who spends his time fishing at the pier and, to his incredible surprise, fishes up Muromi, a mermaid. Muromi first off doesn't realize she's a mermaid until she meets Takurou. Not only that, she is incredibly dense and crazy and has a drinking problem to top it off. Now every time Takurou goes fishing, Muromi appears and makes life interesting for him.

Source: Mangaupdates

Note: The first 2 episodes received a special pre-air at event. Regular TV airing started on April 7.

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Side story: Namiuchigiwa no Muromi-san: Pangea Choutairiku no Muromi-san