Nygma will close in on Isabella's killer in the upcoming episode of "Gotham" season 3.

In the previous episode, Penguin plotted to kill Isabella. Isabella reminded him so much of Kringle that he could not help but fall in love with her. However, he was jealous that Nygma was spending more time with her than him, so he thought that killing her would be best. When she suddenly went missing, Nygma came to Penguin to tell him that Butch was his primary suspect for the murder.

As Penguin started to give more attention than necessary to Nygma, Butch was infuriated as he could not accept the fact that someone else would take his place as his sidekick. Nygma then decided to make it appear like Butch was betraying Penguin. The idea worked, since Penguin sent Butch away. Now that he already knew his true colors, Nygma could not wait to kill Butch. He told him that he planned on killing Penguin himself before they parted ways.

However, Nygma's suspicion that Butch is the killer might just be a trick to make Penguin think that he is totally not onto him. It is possible that Nygma is just waiting for the right time for Penguin to confess. The next episode will reveal if Nygma will figure out that Penguin is the real killer.

Meanwhile, the promo for episode 10 also reveals that unidentified men will attempt to kill Mario, so Falcone will ask for the help of Jim. The synopsis reads, "On the eve of the rehearsal dinner, a threat to Mario and Lee is exposed, and Falcone looks to Jim for help. Meanwhile, Nygma seeks revenge and Bruce learns more about The Court of Owls."

"Gotham" season 3, episode 10 airs Nov. 21, 8:00 P.M. on FOX.