From JanimeS:

The world of Siesta is set in fantasy Europe where there are people called bullet users who were discriminated against badly for reasons unknown to readers as of volume 1.
The discrimination has gotten much weaker due to Grande Corp's efforts to wipe out the decades-old pirate faction with the help of Bulletron, a battle suit designed exclusively for bullet users.

The story begins as the protagonist Dia Canto tells you a little bit about herself: how she became an orphan, how she met her foster family, and how she is very much in love with her step brother, Loe. However, her affection toward Loe is brutally crushed before it would even bear fruit and she goes out to vent her sadness. This is when she encounters Cid Leon, who she would ultimately be paid to "protect".

Apart from the fact the color of her eyes turn red when moon rises, Myung-Ee is your average, albeit boy crazy, 5th grader. After picking a fight with her classmate Yu-Da Lee, she discovers a startling secret: the two of them are “earth rabbits” being hunted by the “fox tribe” of the moon. Five years pass and Myung-Ee transfers to a new school in search of pretty boys. There, she unexpectedly reunites with Yu-Da, but he doesn't remember a thing.

Lang-bee knows the value of money. After her mother runs a vitamin drug scam and goes on the lam, Lang-bee is alone to fend for herself. Lang-bee repays the people scammed by her mom with the money she makes working for her fellow students. When she pursues her love interest in Dan Won, the rich, emotional heir to a corporate empire. Lang-bee competes against Yuka Lee, her nemesis, in the chase for Dan Won. Who will he choose? (Source: Tokyopop)

When Tae Yeon Im finds out that the idol star that she's adored for ages is currently attending the same school as her identical cousin, Jung-Woo Im, she convinces her cuz to exploit their similitude and switch places, she will dress as him, attend his school and try to get close to her lover boy. And he will dress as her, attend her school and revel in its sea of babes. Or maybe he just likes wearing a skirt? The plan seems flawless until Tae learns of a bully named Ga-Wun Kim who likes to beat up on poor Jung-Woo. Meanwhile, Jung-Woo finds that being a woman might not be as thrilling as it seems. New love story begins when Jung-Woo & Tae Yeon switch back to their own original identity. New characters starts appearing and now the story is focusing about Jung-Woo and his friends. What sort of love story that is going to begin this time? Let's find out.... :)