The upcoming episode of "Arrow" season 4 will see Diggle in captivity. The synopsis for episode 20, titled "Genesis," reads:

"As Oliver (Stephen Amell) and Felicity (Emily Bett Rickards) look for a magical solution to defeat Darhk (guest star Neal McDonough), a vengeance-driven Diggle (David Ramsey) is going to get a lead on Andy's (guest star Eugene Byrd) whereabouts and will head off to confront his brother. In the meantime, Alex (guest star Parker Young) will take Thea (Willa Holland) on a vacation that quickly turns into a nightmare."

A trailer has also been released for the new episode and it shows Oliver vowing revenge for Laurel's (Katie Cassidy) death. The clip also shows Diggle facing off with an assailant, but it seems that things won't go according to his plan. Based on the video, it looks like Diggle will be held captive by Darhk and tortured by one of his cronies. Fans are undoubtedly fearful for his life and hope that everything will turn out fine for Oliver's confidant.

Meanwhile, here is a recap of what happened in the previous episode, titled "Canary Cry."

With Laurel's death still fresh in their minds, Oliver and the others tried to plan out their next move. After finding out that Laurel's sonic device had gone missing, Oliver and the team found out that someone has been posing as the Black Canary—Evelyn Sharp.

Captain Lance, Laurel's father, was naturally in grief and attempted to look for a way to bring his daughter back to life. Lance even asked Nyssa al Ghul for assistance.

Diggle, on the other hand, went after Ruvé Adams, Darhk's wife, in order to get revenge. Luckily, Oliver managed to stop it in time because he knew Diggle would regret the act. Ruvé used the incident to turn the tables on the vigilantes, though. Evelyn tried to go after Ruvé, but was stopped by Oliver.

The episode ended with Oliver and the rest of the team at Laurel's funeral, remembering her as the Black Canary.

"Arrow" season 4 episode 20 will air on Wednesday, May 4 on The CW.