Nightmare Inspector: Yumekui Kenbun Vol. 4 (manga)

Shadows

Dreams on the menu in this volume: a man and woman trapped on a malevolent streetcar, a mysterious woman with a possible key to Hiruko's past, letters in a bottle that aren't the usual call for help, a young girl who dreams of a miserable future, a boy being chased by shadows, and a nightmare in which Hiruko himself disappears!