Hana to Oyogu

College student Sasakawa Kouta has a high sensitivity to the other-worldly. One day while walking home, he meets a floating young ghost girl named Kikuko. After being scared out of his pants, once he gets to know Kikuko, he realizes that she is not dangerous. With the help of the people around him, Kouta and Kikuko work together to find out why and how Kikuko died and became a ghost.

(Source: MangaHelpers)