In order to track down Diaz from inside prison, Oliver realizes that will require aligning with an old enemy. Meanwhile, in Star City, Felicity’s attempts to root out Diaz are thwarted by Diggle, whose allegiance to ARGUS now requires him to keep civilians like her on the outs. Realizing that she can no longer rely on her old team or old methods, a clear-eyed Felicity resolves to find a new way to go after Diaz.

Felicity learns something new about Oliver that shocks her. Meanwhile, Diggle asks Curtis to go undercover for ARGUS. Dinah works with an unlikely ally.

Rene fights to help the new Green Arrow's mission, and Oliver, now working with the SCPD, finds an unexpected link to the mysterious vigilante.

After months of covertly pursuing Dante, Diggle and Lyla finally have a solid lead on the elusive terrorist, so they deploy the ARGUS Ghost Initiative to apprehend him. Meanwhile, Oliver tries to bond with Emiko.