The CW has released the official synopsis for "Schism," the fourth-season finale of Arrow which will air on May 25 on The CW.

John Behring directed the episode with story by Greg Berlanti and teleplay by Wendy Mericle and Marc Guggenheim.

Oliver (Stephen Amell) teams up with a surprising force in an attempt to stop Damien Darhk (guest star Neal McDonough) and his magic once and for all.

Arrow airs on Wednesday nights at 8 p.m. ET/PT on The CW.