Lila can't stop bragging about the trip her dad recently took to Hawaii for business. Not only did he promise her that he would take her when she turned 10, but he also brought her back a necklace made from seashells that you can't find anywhere else in the world. Hating that her friend is the center of attention, Jessica keeps claiming that she sees monsters in the school yard and on the road. Elizabeth eventually reminds her of the boy who cried wolf.
The kids are all excited because they're taking a field trip to a water preserve. While all the other kids wore practical and sensible clothing like shorts and running shoes, Jessica refused to wear anything but her new outfit, which consists of black patent leather shoes with slick soles and a blue sailor outfit. This limits what she can do and leads to her walking way slower than everyone else.
While looking at a pool of water, Jessica sees a figure with long hair and big eyes that then disappears. She runs off to tell her friends that she saw a real mermaid. Naturally, no one gives a crap or even believes her. They would rather pay attention to Ellen because she decided to find all the same seashells as those on Lila's necklace and make one of her own. Lila keeps saying she'll never find the same ones, but Ellen finds all but one and then finds that one too. This makes Lila pout more than usual.
No one believes Jessica, not even her own twin. Every time that they ask her to play or do something with them, she refuses unless they say they believe her. Liz finally says that she believes her twin saw something in the water and convinces her that she should tell their teacher. The teacher agrees with Travis, their tour guide, that they should do back and take a look.
This time, Travis does see something in the water and pulls out a sea lion cub. The hair Jessica saw was some seaweed wrapped around her. Travis says that cubs often get abandoned and that they can save and rehabilitate her. Jessica gets to cuddle with the lion for a few minutes. Travis says she can name the cub, and Jessica picks the name Mermaid, so she can really say that she saw a mermaid.
Their teacher takes her to the side and has a long talk with her about how you should always tell the truth. Jessica agrees, they share a brief moment, and then she runs off. Carolina gives her a pair of spare shoes so she can have fun with all her friends before they all go off on something completely different.
*Jessica puts out that 10 is a long time from now and that Lila's dad might forget about his promise. It's an ouch moment given how often he forgets about her later.
*You would think that the teacher might call the Wakefield house and let them know that their second grade child keeps lying all the time, but that might have stopped Jessica from becoming even worse as a teenager.
*I love that Ellen actually found all the same seashells and made her own necklace. It's nice to see her being a normal kid who everyone likes!