In the near future, Earth is at war with aliens called Worms. The war leaves the population of Earth decimated, with young men the main casualties. The Worms were beaten back but their re-emergence heralds the creation of a mecha unit called the Sonic Divers, piloted by 3 young girls to counter this threat. (Source: ANN)

In these earlier adventures of Lina Inverse and Naga the Serpent, learn how the two rivals first met. In their first adventure, the two rivals meet and run into a vampire during a rescue mission. Next, Lina is hired to be the bodyguard of a rich man's daughter, Sirene. Lina is at first very enthusiastic about it at first, as she is being paid very well, but Sirene keeps spending all of Lina's first half of pay. (She gets the other half later) She puts together a fake kidnapping to teach Sirene a lesson, but when she really gets kidnapped, she must team up with Naga to save her. In the final episode, Lina and Naga find themselves on seperate sides in a fashion war. (Source: ANN)

In order to pursue her dream of bringing positive changes to Japan, Mitsumi Iwakura leaves her countryside town to attend a prestigious high school in the hustle and bustle of Tokyo. As she has already mapped a clear life plan, she has absolute confidence that there will be zero mishaps from then onwards. Despite her ambitious promise, the country girl ends up running late on the first day when she gets lost on her way to school. Fortunately, she meets a fellow first-year student, Sousuke Shima, who is in the same situation and offers to go with her. They eventually make it to school, but the misfortunes do not end there, as Mitsumi leaves an unfavorable first impression in front of her classmates. Nevertheless, the class soon takes notice of her friendship with Sousuke despite their opposing personalities. Only time will tell whether Mitsumi will be able to forge fruitful relationships with her classmates, and she will certainly not be alone.

At Kaimei High School there is a special club dedicated to helping others known as the SKET Brigade. The brains of the group is Kazuyoshi Switch Usui, a tech-savvy otaku who speaks through speech synthesis software, while the brawn is provided by Hime Himeko Onizuka, the hockey stick-wielding girl once known as Onihime. And last but not least, their leader is Yuusuke Bossun Fujisaki, whose latent ability is evoked by his goggles, allowing him to summon the awesome power of extraordinary concentration. However, most of the school only know them as the club that handles odd jobs. Many of their days are spent in the clubroom slacking off, but when there is something to be done, they give their all to help others—usually in sincere, but unintentionally hilarious, ways. The SKET Brigade do all they can to provide support, kindness, encouragement, and troubleshooting to any students crazy enough to ask for their services.