Check out a sample of the 23 images featuring Summer Glau as Isabel Rochev, Caity Lotz as The Black Canary plus many other familiar faces (updated with high resolution version) and head over to the forum for the rest of these great images.
Here's the official description for Arrow 2x04 'Crucible':
OLIVER MEETS THE CANARY — Oliver (Stephen Amell) discovers a man who goes by the name “The Mayor” (guest star Cle Bennett) is bringing illegal guns in to The Glades, so Oliver sponsors a “Cash for Guns” event to help clean up the city. Unfortunately, The Mayor crashes the event with his gang and seriously injures Sin (guest star Bex Taylor-Klaus). The Canary (Caity Lotz) is furious when she learns her friend is in the hospital and sets out for revenge. Meanwhile, Felicity (Emily Bett Rickards) stuns Oliver with a bit of information about the Canary, Donner (guest star Dylan Bruce) asks Laurel (Katie Cassidy) to dinner, and Diggle (David Ramsey) reconnects with an old friend. Eagle Egilsson directed the episode written by Andrew Kreisberg & Wendy Mericle (#204).
This episode airs on Wednesday, October 30 at 8pm on The CW.
To those who tought Laurel Lance, played by Katie Cassidy, was going to be Black Canary, the producers have said a while ago that the Black Canary that we are seeing now is the first one, Laurel will be replacing her eventually. Just like Yao Fei was the first Green Arrow and Billy Wintergreen the first Deathstroke.
really looking forward to seeing Summer Glau back, as for the Black Canary she looks absolutely wicked cant wait to see her as well, looking forward to seeing episode, after episode they just cant come quick enough, that will be really fascinating when eventually, Laurel enters the picture as the Black Canary, would that mean Oliver would not know who Laurel was, and Laurel would not know who Oliver was, with them both being in disguise. Hmm Interesting.
Laurel Lance (Katie Cassidy) as the Black Canary is not going to happen until next year, at best. And since it's unlikely Summer will be there next season (but who knows), we won't be reporting it in the News section