Stephen Amell as Oliver Queen, Emily Bett Rickards as Felicity Smoak and David Ramsey as John Diggle in 'Arrow'.Facebook/Arrow

"Arrow" season 4 returns with new details of Nanda Parbat and Lazarus Pit as Laurel Lance (Katie Cassidy) and Thea Queen (Willa Holland) seeks Malcolm Merlyn's (John Barrowman) help for the resurrection of Sara Lance (Caity Lotz). Episode 2 is titled "Restoration" and it may feature Curtis Holt as the new member in Team Arrow.

The official synopsis of the sequel read as below:

The growing tension between Oliver (Stephen Amell) and Diggle (David Ramsey) puts both their lives at risk when they go after Damien Darhk (guest star Neal McDonough) and a H.I.V.E. deployed meta-human. Meanwhile, Laurel (Katie Cassidy) talks Thea (Willa Holland) into returning to Nanda Parbat to ask her father (John Barrowman) to put Sara (guest star Caity Lotz) into the Lazarus Pit. However, Laurel is surprised when Nyssa (guest star Katrina Law) refuses to do it.

CLICK HERE to watch the sixth episode of "Arrow" season 4 online on The CW this Wednesday, 21 Ocotber, at 8pm.

In a sneak peek video, executive producer Wendy Mericle teases an exploration of the differences between Oliver and Diggle. "We are going to explore the reasons why he and Diggle are still at odds. Basically goes back to what happened at the end of season 3 When Oliver made the decision to try to take down the League of Assassins from the inside and wound up kidnapping Lyla and endangering baby Sara," she says.

Meanwhile, cast member Barrowman teased about the resurrection of Sara and Tommy. "I know that Malcolm is greatly affected and hurt by what happened to Tommy. But when you watch tonight, you'll see where Malcolm stands on the fact of this resurrection thing, because it's not like it's a spa where he's like, 'hey, come on in, let me resurrect you!' He wanted control of that for himself," he told Variety.

"Arrow" airs on The CW every Wednesday at 8pm.

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