I don't remember the story, but it kinda had a vibe similar to June's Journey, where you would travel to different places o find objects in intricate sceneries and progress the story. I know it was a mystery game, and some of things you had to find where blood trails, footprints and such.
There where three main characters: an old man, a young boy and a girl (who I turned out to be a vampire or something of the sorts). The game cartridge was blue.
I really can't remember anything else about other than having good background music. It was available for the first psp.