By Natalie Abrams
October 29, 2014 at 04:45 PM EDT
Ed Araquel/The CW

Malcolm Merlyn is returning to the scene of his most horrendous and heinous crime: Starling City.

The season-one big bad left the town behind after Moira (Susanna Thompson) relayed word back to League of Assassins leader Ra’s al Ghul (Matt Nable) that Malcolm (John Barrowman) had, in fact, survived the Undertaking—the very event that violated the League’s code of honor, making him an enemy to Ra’s. But he’ll return during Wednesday’s episode of Arrow, and it won’t be long before Oliver (Stephen Amell) discovers that the Dark Archer is still alive. It should come as no surprise that Oliver suspects Malcolm had a hand in Sara’s (Caity Lotz) death.

“Episode four is really a referendum on whether or not Malcolm Merlyn lives and it’s a choice that Oliver gets to make,” Amell tells EW from the Vancouver set. “We get to see how much he follows his moral compass in episode four. There are things that Oliver blames Malcolm for that extend far beyond the fact that he may or may not have killed Sara. You get back to Tommy [Colin Donnell] and the whole chain of events that devastated Starling City. He’s really at the center of everything that’s happened that’s bad on the show since its inception.”

Malcolm’s return to Starling also coincides with Nyssa (Katrina Law) coming to town to find out what happened to Sara. “Oliver and Nyssa disagree about their tactics, but when she returns to Starling City, they very much have a common goal, and that’s to find whoever killed Sara Lance,” Amell says. “How Nyssa and Oliver are dealing with Malcolm and want to deal with Malcolm, that’s where they come to blows in the episode.”

“Everything that’s happening with Sara and Nyssa’s involvement is all leading to a much bigger conflict which is really the crux of our first nine episodes,” Amell continues. “By the end of episode four, there is a ticking time bomb in the form of the League of Assassins that is over Oliver’s head. Oliver is so protective of his process and his city that by the end of episode four, he makes enemies with the League.”

Another challenge that comes with Malcolm’s arrival is keeping his pledge to be honest with Thea (Willa Holland). “When Oliver learns that Malcolm is alive, one of the people he has to tell is Thea and that certainly creates some tension,” Amell says, noting that Ollie is unaware that his sister not only knows that information already, but she’s been under his tutelage for the last several months. “If that happens, that’s a ways down the road.”

Arrow airs Wednesdays at 8 p.m. ET on The CW.