During her summer holiday at her grandparents house Tamai Shiina, a young and cheerful schoolgirl, meets a strange looking creature. They befriend each other and Shiina names it "Hoshimaru: The Round Star." When Shiina returns home after the summer to go back to school, she starts meeting other kids that also have befriended a strange creature like Hoshimaru. But she soon finds out that not all these creatures and their masters are as friendly as Hoshimaru.

Metropolis of music, MIDICITY. A kitty girl wearing gothic lolita clothing named Cyan is scouted by Maple Arisugawa, the president of a music agency. From there, she meets Chuchu (a pun off of the sound that rabbits make) the honor student rabbit girl, a net geek dog girl named Retoree (from "Retriever"), and an alien sheep (?) girl named Moa. Together, they form the band named "Plasmagica," and aim for the top of the world. However, the path there is long and tough, and keeping in high spirits is important. By battling against other strange bands, Plasmagica slowly grows toward a top-grade band. In the end, they'll be a band that becomes the driving force of MIDICITY's music industry... Maybe? Gonna be a music millionaire! (Source: Sanrio)

Lum doesn't need much assistance going ballistic when everyone in Tomobiki gets an invitation to Ataru's wedding -- and she's not listed as the bride! It seems that some 11 years ago, Ataru played "Shadow Tag" with a young girl named Elle and won. Unfortunately, Elle was yet another Alien Princess; and on her planet, if a boy steps on a girl's shadow, they have to marry. 
When Elle's emissary comes to make arrangements, Lum redefines the term "the atmosphere was electric," but to no avail: a force-field now protects Ataru from her high voltage love-zaps. Lum's friend Benten suggests a pre-emptive wedding, and they proceed to abduct Ataru and all of the wedding guests, and the stage is set for the shotgun wedding of all time!

Ritsuka Tachibana. She lives a calm and unchanging life. Ritsuka's older brother Lindo returns from studying abroad in the United Kingdom. Shikou Academy student council president Rem Kaginuki calls on the girl, and she begins having mysterious encounters with the student council members. Her life changed a little from that day, but Ritsuka expected nothing more. However, she comes home to find her mother collapsed with suspicious hooded men nearby. They were not human but devils, vampires, and exorcists seeking the Forbidden Grimoire. Ritsuka's former daily life crumbles around her, and she finds herself slowly becoming attracted to Rem, who helps her in her predicament. On the other hand, confusion deepens with regard to her brother who carries a secret. Ritsuka is unsure what path to choose as she finds herself at the center of a love story.