Elementary season 3 episode 15
Elementary stars Jonny Lee Miller as detective Sherlock Holmes and Lucy Liu as Dr Joan Watson CBS

The fourth season of Elementary is down to its last episode, and as fans prepare for the season finale, executive producer Robert Doherty has revealed what lies ahead for the detective-surgeon duo of Sherlock Holmes and Joan Watson. Episode 24 titled, A Difference In Kind, will have Holmes and Watson discovering a criminal network that poses a potential threat to their lives. The final episode airs on 8 May 2016 on CBS at 10 pm EST.

The official synopsis of the episode reads as follows:

In the previous episode, when Holmes' father Morland was faced with an unknown threat with a Russian hitman bombing his office, Holmes and Watson were forced into taking the case and hunting down the old man's attacker. In the process, the duo realised certain facts that could possibly hint towards the season finale twist. With Moriarty behind the bars, Holmes is certain that someone else is wielding power in the organisation, which takes him to a rather ambiguous person in professor Vikner. He not only turns out to be the new caretaker, but also the father to Moriarty's child.

Warning: Potential spoilers ahead, proceed at your risk

The Russian hitman's identity is revealed, and Holmes and Watson put the case to rest with Kraznov getting arrested. However, everything does not end with the arrest of the killer; it appears the detective duo underestimated the power and reach of the mysterious perpetrator, whose revenge plans involve getting back at both of them. With the intrusion in the plan, the hitman is aiming straight for the duo's heads, it is to be seen whether Holmes and Watson will make it alive from the manhunt in the finale episode.

Amidst all the action, Rob Doherty bears pleasant news for Elementary fans as the show is getting renewed for its fifth season. Talking to TV Line about the future prospects, Doherty said that they may bring Joan's half-sister Lin played by Samantha Quan back to the narrative. "We'd love to see her again next year," Doherty said, "It's a matter of finding the right kind of story to pull Lin back in," he added.

Liu too spilled some beans to Hollywood Life about the big finale. "Normally, we have a lot of smaller stories involved, but this is a continuation of his father and the story and how that will conclude," revealed the actress adding that the ongoing drama between Sherlock and his father could be a game-changer.

Click here to watch Elementary season 4 episode 24 titled A Difference In Kind live online.