The fourth season finale for "Arrow" is titled "Schism," but whether that refers to a metaphorical gap forming between members of Team Arrow, or a literal rupturing of the ground beneath Star City remains to be seen. Oliver does look a little frustrated with Diggle in one photo, though.

"Arrow" Season Finale Trailer Shows an All-Out War in Star City

What we do know is Damien Darkh's plans for Green Arrow's hometown will come to a head, and whatever the outcome, it's sure to spell trouble for Oliver and his friends.

The finale's synopsis also teases a "surprising force" helping Oliver out in his battle with Darkh, though who -- or what -- that is remains a mystery.

OLIVER TEAMS UP WITH A SURPRISING FORCE TO STOP DAMIEN DARHK -- 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's" Season 4 finale airs Wednesday, May 25 on The CW at 8 p.m.