15 year olds named Rosa, Samantha, Sirena, and Alexandra. Samantha nickname is Sam and Alexandra nickname is Alex the girls have all been friends since 5th grade and now in 9th grade well finishing it up until it was summer vacation, they all are sirens who come from the island "Sareena" where sirens are born and it is like a island realm where the sky is different the sea color is light pink and purple it is a very beautiful place there. There is this secret agency named "W.H.M.U.A.A.M.C." it means "We help magical user and Mystic Creatures" they protect them, and help them out and help humans the people who run it are Inhumans who have special abilities and basically no humans know about it only Fairies, Inhumans, and Sirens which are mermaids. How they got invited is that they got a letter saying "we would love to invite you girls to the agency, let us talk more in person." The girls didn't trust so Rosa older brother Damian who is engaged at 17 turning 18 soon came.

Jerry explained everything since sirens know the sea could help them out a bit with protecting others. they thought about it. This all happened in April and the parents were not supposed to know about this so Rosa brother Damian said he wouldn't tell their parents, he use to be apart of it a long time ago so he knows they'll keep them in good hands since he still has friends who are still in the agency and introduced them to them and he had a lot of friends and knew Damian sister as the "little sister of Damian." They joined afterwards getting trained.

(Checkout more in the desperation about the characters.)

Brandon who goes to the same school as them since they go to a human school planned a pool park party Sirena was on the chair relaxing reading a fashion book, Sam reading a history book, and Alex drinking slushie. Rosa gets a msg from Jerry saying a troll who can disspear/shapeshift is on the loose, she looks serious now.

Sirena: looks at Rosa oh no, another mission!

Sam: looks at Sirena quit being dramatic

Alex: she laughs