The "Elementary" season 4 finale will show Sherlock walking down memory lane, but a promo video for the episode suggests that it will give him more disturbing memories than good.

The last two episodes of the series will air on May 1 and 8. The new promo released for both episodes hint at the possibility of a new character haunting Sherlock.

According to TV Line, actor Tony Curran is going to appear in the penultimate episode of "Elementary" season 4 on May 1 as Joshua Vikner, an economics professor who will show much interest in Sherlock's nemesis Moriarty. The news has led fans of the series to speculate that Curran could be the one troubling Sherlock Holmes.

While it has not been confirmed yet if Moriarty will appear in the last two episodes, fans are excited to know more about the character of Vikner and his connection with Moriarty. This could spark some interesting discourses between Sherlock and Morland.

Fans speculate that even if Dormer does not appear in the next episode, knowing Vikner's mysterious character's connections with Moriarty reminds them that her character is still out there and that she will be back to the limelight eventually.  

Meanwhile, it was confirmed recently that "Elementary" has been renewed for a fifth season. This means that some elements of the finale may be carried over to the future. Such elements include the character of Vikner who is going to debut in the penultimate episode on May 1, and what Moriarty has been up to since her disappearance.