Taken from Serenus-Dreamers:

Admitting herself as super unlucky person, Ritsu, freshman in high school, tries to get out of unluckiness and disasters by living in the school dorms and starting fresh. However, with her destined meeting with school's famous genius as well as problematic student Eiri, Ritsu starts to get unluckier everyday....!?

From Tokyopop:
When Kazura Enomoto’s grandfather dies, he leaves her to the son of a rich family, Mizuki Magahara, as payment for his debts. After she goes to live with him, Kazura learns that she’s not going to be working off the debts as a servant—she’s going to be Mizuki’s fiancée! Unless Kazura can repay her debt, she’s got no choice but to learn to live with her new lot in life. But no sooner has Kazura begun to adjust to living with Mizuki and going to his snotty rich school than the dark secret of the Magahara family comes to light. The head of the family has the unique power to bring back the souls of the dead—and right now the head of the family is Mizuki!

Ever since she was a little girl, Hatsuse Nanao has had trouble making friends because she can see ghosts and demons that others can't. She thought things might improve in high school with new classmates, but the rumors have somehow started up there, too. Finding all the stares and whispers uncomfortable, she feigns being sick to skip school for a few days, and runs into a strange little boy at the park who knows her name and demands to spend the day with her. While trying to figure out who he is, she's discovered by Yatou Kaname, her class rep, who lets them stay at his place for the night. Who is this strange little boy and why does Yatou seem to so strongly hate even the idea of sprits and demons? Nanao finds these answers in both her own past and Yatou's.