The CW has released the first promo for Arrow Episode 6×18, which you can watch above.
Titled “Fundamentals” and set to air April 12th, the episode is officially described as follows:
“OLIVER IS VISITED BY A GHOST FROM HIS PAST – In his darkest place yet, Oliver (Stephen Amell) wonders if he has failed at everything – being a father, a mayor and a hero. His frustration rising, Oliver lashes out at Felicity (Emily Bett Rickards) and William (guest star Jack Moore). A surprising visit from an old friend has Oliver questioning his next move.”
Ben Bray directed the episode, written by Speed Weed & Emilio Ortega Aldrich.