The synopsis for the upcoming episode of Arrow's second season, which was revealed on April 27, reveals that Slade will unleash his assault on Starling city.

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So it seems like Oliver will throw himself into the line of fire after going in hiding for a bit in the upcoming episode titled City of Blood. As the idea of him surrendering to Slade's army is nothing short of suicidal, Felicity will venture to save him.

CW also revealed new stills from the episode which focus on the ultimate battle between Slade and Oliver. In one shot, Slade seems to have almost gotten Oliver, as he is seen choking him, but Felicity lurks in the background, ready to attack Slade.

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Here's the official synopsis for City of Blood:

"OLIVER CONSIDERS HIS OPTIONS AGAINST SLADE - After Slade (Manu Bennett) threatens to take everything Oliver (Stephen Amell) loves away, Oliver decides the fastest way to stop further bloodshed is to surrender to his enemy. Knowing that surrender will surely lead to Oliver's death, Diggle (David Ramsey) and Felicity (Emily Bett Rickards) go to extreme measures to keep Oliver from confronting Slade. Meanwhile, Thea (Willa Holland) considers leaving town, and Laurel (Katie Cassidy) resumes her crusade against Sebastian Blood (guest star Kevin Alejandro). Finally, Slade unleashes his assault on Starling City. Michael Schultz directed the episode written by Holly Harold (#221)."

City of Blood will air on May 1 on CW. 

Watch the preview for the episode here"