Originally created by Neil Gaiman.

About couple of dead kids who end up running a detective agency.

From the American Library Association:
Ghosts Edwin Paine and Charles Rowland, introduced in Neil Gaiman's fourth Sandman opus, Season of Mists (1994), and featured in Thompson's At Death's Door (2003), are still avoiding Death and still finding time to run their own detective agency. Their latest case brings them stateside to a girls' boarding school in Chicago. While undercover, they work their way through the clues to find an absent classmate. They and their new friends at the school suspect the worst, and the teachers' mysterious attitude about the missing girl isn't helping. Thompson's cute art, distinctive while remaining within traditional manga-anime conventions, fits a story full of well-written over-the-top screwball comedy and featuring cameo appearances by Death and the Sandman. Sandman series fans may be a little disappointed (it's too cute), but manga mavens will be in heaven.