"Arrow" season 4, episode 19 will see Diggle (David Ramsey) still blaming himself for what happened to Laurel Lance (Katie Cassidy).
In the previous episode, Laurel passed away after Diggle didn't believe his best friend Oliver Queen (Stephen Amell) that his younger brother Andy was working with Damien Darhk.
As such, Damien was able to kill Laurel, and the upcoming episode will see all of the members of Team Arrow mourning her demise.
In the teaser released by The CW for "Canary Cry," Felicity Smoak (Emily Bett Rickards), Thea Queen (Willa Holland) and Oliver could be seen crying while listening to the pastor's speech about death.
The next scene showed Oliver telling Diggle that Laurel is gone and won't return anymore so it's not a good idea for him to dwell too much on the past.
"Laurel is gone. If she was right here, she would tell you that you cannot forget who you are," he said.
The next scenes showed Diggle going ballistic on the streets, tormenting people, and even pointing a gun at the other mayoral candidate at Starling City.
"We can never become them," Oliver reminded him.
Meanwhile, here's the complete synopsis from episode 19: "The team struggles to deal with Laurel's death; Diggle is overwhelmed with guilt over choosing to believe that Andy had changed; Lance refuses to believe his daughter is gone."
In an interview with Entertainment Weekly, cast member Paul Blackthorne said that it is his character Quentin who will feel the impact of Laurel's death the most.
"This death is just devastating for Lance, because this is not the one that was ever supposed to happen. Personally, I was almost as devastated as Lance, to be honest, with the news of this happening, because Katie and I have had such an amazing working relationship that it actually really is hard to accept. In terms of Quentin, he's going to have to pick up the pieces, not pick up a bottle, and reconcile what's left in his life. With that, he's got the Arrow family," he said.
"Arrow" season 4, episode 19 will air on The CW on April 27 at 8 p.m. ET.