The CW has released the official synopsis for “The Candidate,” the forthcoming second episode of Arrow’s fourth season.

“Haunted” — (8:00-9:00 p.m. ET) (TV-14, LV) (HDTV)

MATT RYAN REPRISES HIS ROLE AS JOHN CONSTANTINE ON ARROW — When things take a turn for the worse with Sara (guest star Caity Lotz), Oliver (Stephen Amell) calls in a favor from an old friend who deals in the mystical, John Constantine (guest star Matt Ryan). John Badham directed the episode written by Brian Ford Sullivan & Oscar Balderrama (#405).

Original airdate 11/4/2015.