Diggle (David Ramsey) and Felicity (Emily Bett Rickards) are shocked by Oliver’s (Stephen Amell) decision to call on the Bratva to help take down Prometheus (Josh Segurra). Concerned the Bratva may overstep, Diggle has a hard conversation with Oliver about what happens if things go south. Meanwhile, Felicity learns something shocking at Helix. J.J. Makaro directed the episode written by Rebecca Bellotto (#518). Original airdate 3/29/2017.