Well, if there is going to be a season 4 of Sleepy Hollow then it'll look a bit different as S3 is ending up cleaning house & rebooting itself.
Actress Nicole Beharie who plays Abbie Mills, one of the two main characters, has confirmed that she is exiting the show. This follows last week's death of character Joe Corbin, son of Sheriff Corbin from S1 and love interest of Abbie's sister. Unlike some other character deaths in the show, these two are permanent.