Hinako Yaotose is in the sea in This Monster Wants to Eat Me episode 1. She says that she can hear the sound of the sea waves when she closes her eyes. She can also see the color of the deep sea. She’s filled by the scent of summer in the days of emptiness. We see a girl Shiori who has a pair of eyes like deep sea. Hinako reveals she and Shiori encountered.
Hinako is sleeping at home. She’s woken up by the alarm clock. She gets up from the bed. She glances out the window. She checks her messages on her cell phone. Her aunt cannot come back. But she thinks Hinako’s parents will be happy in heaven because Hinako became a high school student. Hinako receives a message from Miko. Miko asks Hinako to go to the school alone because she knows she will be late. Hinako sighs after she put down her cell phone. She sees her family photo. Her parents and her brother are in the phone. They smile when they enjoy the summer. Hinako says that she doesn’t want to live.
Hinako goes out. She walks alone the seashore. She remembers she asked her brother to wait for her when he ran to her parents. But she was told to be fast because her parents were waiting for her. Hinako approaches the railing. She says that she hates summer because of the sadness. She hopes summer to pass quickly. The large bubbles rise to the surface of the sea. Hinako observes the bubbles. She guesses something is in the sea. She stands on her tiptoes. She wonders if it’s a big fish.
Someone stops Hinako with her hand. Hinako is startled. She turns around. She sees the girl Shiori. Shiori tells Hinako that it’s very dangerous. A gust of wind blows past. Hinako is shocked when she looks at Shiori. She thinks she’s deep like sea. Shiori tells Hinako that it’s a problem that he was drawn by the sea. But Hinako shouldn’t have leaned out. Because it’s too dangerous.
Hinako doesn’t believe that she would fall into the sea. She thinks it’s fine. Shiori lets go of the girl’s hand. She feels sorry. It promotes Hinako to think that Shiori is weird. Shiori explains it to Hinako that she mistook that she would jump into the sea. Hinako is shocked when she opens her eyes wide. She remembers her mother wished her to live. She tries to leave. But she turns around. She asks Shiori not to say strange things. Shiori learns that her words made the girl feel uncomfortable. She smiles at Hinako. She apologizes to her. She wishes her to be careful.
Hinako arrives at the school. Miko says good morning to Hinako. She apologizes to her that she wasn’t with her. Hinako wonders what happened to Miko. She guesses her friend overslept. Miko denies it. She explains it to Hinako that she forgot to dry her school uniform and sleep. She coughs when she says that she used the hair dryer to dry it. Hinako guesses Miko’s cold hasn’t cleared up. Miko laughs. She says that she’s fine. But she worries about Hinako. Because she knows she was alone. She asks her if she was tangled by any weird person. Hinako thinks she’s not a kid.
The two girls show up. One of the girls thinks Miko overprotected Hinako. Miko talks back that she worried about Hinako because Hinako was easy to encounter strange things. She mentions Hinako tripped on flat ground. Hinako is in the sea when Miko talks to the two girls. She sees some big fish. Miko calls Hinako. Hinako comes back to reality. Miko asks Hinako what happened. Hinako denies it when she smiles at Miko. Miko doesn’t believe it. The teacher walks into the classroom. She asks the students to go back to their seats. Hinako says that her heart sank to the bottom of the deep sea since that day. She remembers Shiori. She wonders why she thinks the girl is like sea.
Hinako tries to opens her locker after school. Miko stops Hinako. She offers to go to the bookstore before they go home. She mentions the convenience store is selling the new dessert. Hinako agrees. But Miko is told that she needs to complete the papers before she leaves. The Physical Education Teacher also wants to meet Miko. Miko cries. She grabs Hinako’s hands. She expresses that she doesn’t want to take a test. She believes that the teacher will give her a hard time. Hinako points out that Miko will be in trouble if she doesn’t go to see the teacher. She promises Miko that she will wait for her. Miko is full of energy. She swears to complete it quickly. Hinako cheers her friend up. Miko pulls down her skirt. She takes off her necklace. She apologizes to Hinako. She runs away.
Hinako thinks she should find a place to pass the time. She decides to go to the library. But Shiori walks past Hinako. Hinako sees Shiori. She chases her to the seaside. But Shiori is missing. Hinako wonders why she did it. She decides to return to the school. Because she thinks Miko completed the task the teacher gave her.
The hair appears. It tries to drag Hinako into the sea. Hinako trips. She’s scared. The monster appears from the sea. She tells the girl that she got her. She thinks she’s delicious. We find out that the girl’s pant is torn. She injured her knee. The monster Iso-onna reveals she came from West Sea Route. She mentions someone stopped her in the morning. She thinks she can enjoy the food well this time. She drags Hinako into the sea. Hinako is in the sea. She thinks it’s good. Because she can join her family.
But Shiori saves Hinako. She mentions what she said that it’s dangerous. Hinako recognizes Shiori when she’s carried. Iso-onna is angry to show up. She wonders why a mermaid is there. She blames Shiori for obstructing her. She claims that Hinako is her prey. Shiori asks Hinako to hide behind her. She walks to Iso-onna. She thinks she’s just a lowly monster.
Shiori turns into a terrifying monster. She claims that Hinako belongs to her. She kills Iso-onna with her claw. Hinako witnesses the massacre. She thinks it’s a hell. But she can do nothing. Shiori helps the girl up. She asks her if she’s fine. Hinako is surprised that the mermaid knows her name. The mermaid walks to her. She grabs her hands. She reveals she has been looking for her. Hinako is surprised after knowing it. She wonders who is the mermaid. The mermaid tells the girl that her name is Shiori. She smiles to reveal that she came to eat her. She mentions Iso-onna was drawn because Hinako’s meat is delicious. Shiori believes that Hinako will be more delicious. She decides to protect the girl well.
The next day, Hinako comes to the school. She sees Miko’s message in her cell phone. She remembers Miko wondered why she was wet. She thinks she brought trouble to her friend. She walks into the classroom. She sits on her seat and she puts her bag on the desk. She guesses Miko doesn’t come to the school because Miko had a cold again. She gazes out at the sea.
Hinako remembers Shiori told her that she won’t eat her at this time. Shiori asked Hinako to dress her wound. She left. Hinako didn’t understand what Shiori meant. She tries to chase her. But Miko stopped Hinako. Shiori disappeared.
Hinako wonders why the mermaid didn’t eat her. The teacher walks into the classroom. He introduces the transfer student to the students. The transfer student Shiori shows up. Hinako recognizes the girl. Shiori smiles at Hinako. Hinako guesses the girl can fulfill her wish. She reveals she wants to die.