An action comedy film based on the "duplicating humans' invasion" setting derived from Jack Finney's Sci-Fi novel "The Body Snatchers", combining Sci-Fi horror-like story and dance (samba). An authority on biotechnology and a developer of "konjaclone" technology, Amigo Suzuki carries out "Transformation Plans for Samba World", in which he makes human clones using konjac as a material and makes them dance a samba. In Kasukabe city, people switch places with false ones who look just like the real persons. The Nohara family and the members of Kasukabe Defense Forces try to escape from Kasukabe with the help of a mystery beautiful girl Jacqueline Feeney (Jackie).

One year ago, a UFO containing 150 aliens crash-landed off the shores of Kasai. Because no one could fix their ship, the Japanese Government decided to bestow upon them the designation "DearS" and make them into Japanese citizens, teaching them the language, customs, and culture of Japan. However, in order for them to become more familiar with human society, a home-stay program has been enacted to allow them to mingle with other humans. One misty morning, a truck carrying a capsule that housed one of these aliens ends up dropping it into the riverbank, releasing her from her confinement. She is eventually found by a high school student named Takeya Ikuhara, who saves her from being hit by a truck and takes pity on her, despite being extremely distrustful of their race and wanting nothing to do with them. Upon being named Ren, she imprints upon him as her "Master" and serves as his personal "Slave," leaving him with a "DearS" who wants to remain with him no matter what and bringing his ordinary, alien-free days to an end.

Revealing himself to be a Dual Knight, Long Hao Chen triumphs in his match within his temple and advances to the finals. But before the grand finals can begin, ranking matches are conducted in each temple to determine the strongest within. During the rankings, Hao Chen is injured, enraging Sheng Cai'er and driving her to seek vengeance for what happened to him. Her actions cause a fight between the Knight Temple and Assassin Temple, only to be subdued after a shocking revelation—that Sheng Cai'er is a Reincarnated Saint. The finals for the Demon Hunting Team Competition begin with the division of the sixty remaining participants into six groups. The top sixteen participants are then further pitted against each other to determine the top three. Each of the top three will be rewarded with a spiritual stove and the right to pick their teammates. In order to become a knight that is capable of defeating the Demon Lord, Long Hao Chen must strive to be first in this competition so he can select the best teammates to give him a fighting chance.

First loves are messy. While settling in as a shoujo manga editor at the famous Marukawa Publishing House, Ritsu Onodera is quite troubled. Working under the stern and superb Masamune Takano is hard enough as it is. However, Masamune is not only Ritsu's first love from middle school but he also suddenly declares that he will make Ritsu fall for him again. Unknown to them, another editor in the department, Yoshiyuki Katori, is in a relationship with the popular manga artist Chiaki Yoshino. The carefree Chiaki fails to notice, however, that his high school friend—Yuu Yanase—thinks of him as more than a friend. The stoic but caring Hatori will not surrender his love so easily. Falling in love for the first time when you are 30 is certainly troublesome. Shouta Kisa, yet another editor, is going out with 21-year-old Kou Yukina, an art student. Despite Yukina's assurances, Kisa cannot help but doubt whether someone like himself is truly worthy of his younger, "sparkling" boyfriend.