Check out a preview for the next episode of Arrow, 204, "Crucible."
A man called the Mayor brings illegal guns into the Glades, so Oliver sponsors a "Cash for Guns" event to rid the city of weapons. But the Mayor and his gang crash the event and seriously injure Sin. When the Canary learns Sin is in the hospital, she seeks revenge. Meanwhile, Donner asks Laurel to dinner; and Diggle reconnects with an old friend.
Arrow airs Wednesdays at 8pm ET on the CW.