"Arrow" season 4, episode 20 followed the death of Andy.

Based on the synopsis for the episode, Oliver, together with his ex-girlfriend Felicity Smoak, is going to search for a magical solution to take down Damien Darhk. As they delve into the magical arts, John Diggle receives valuable information that could lead him to his missing brother Andy. He then skips out to come face to face with his double-crossing sibling.

As Diggle stumbles upon his brother Andy, Andy stabs him until he finds his way out. However, his escape turns out to be part of Darhk's plan.

Andy sets up a trap for Diggle so he could torture him to death. As Diggle reaches the safe house where Lyla and Sara hide, he comes face to face with Andy again, this time for their one final tussle. After taunting and taunting Diggle that no one is safe from the "Genesis," Diggle finally decides to take down Andy by shooting him at close range.

Trying to comfort John over the death of his baby brother, Lyla realizes that the subdermal implant previously eked out by Darhk from her forearm actually contains the Rubicon program, a flying missile override protocol that has the capacity to stop a nation from launching a bomb, in the same way that it allows for easy launching. However, it makes her wonder too that if "Genesis" is Darhk's way of destroying the world, then how does he plan to restore humanity?

"Arrow" season 4 airs every Wednesday, 8:00 P.M. on The CW.