Arrow 5x16 "Checkmate" Season 5 Episode 16 Extended Promo - OLIVER SEEKS THE TRUTH — Oliver (Stephen Amell) gets closer to the truth about Prometheus. Meanwhile, Helix refuses to continue helping Felicity (Emily Bett Rickards) until she does a favor for them. Ken Shane directed the episode written by Beth Schwartz & Sarah Tarkoff (#516). Original airdate 3152017.