Ok first a few things. 1. I DO NOT OWN RWBY OR Mha and that time I got Reincarnated as a slime the fanart of Izuku and Blake the art goes out to the rightful owners! anyway with that out of the way let's get into it. On a very rainy night we see 3 people running for their lives. Who and what are they running from? Why are they running for there lives in the First place? Who knows will they survive?? Who Or what is out their chasing them m??? Where are they in the first place???? Well I'm here to answer your question but you gotta read the book to find out! 
13 parts