It's not easy to find a black cat in a dark room. It is even more difficult to find a folder with documents stolen from a businessman. Private detective Tatyana Ivanova is convinced of this as soon as she begins the search. She will have to spend the night in the morgue, visit the lair of cold-blooded killers, the crypts of an ancient cemetery - before she finds out what secrets the key to was kept in that ill-fated folder...