'Arrow' Season 2, Episode 18 Spoilers: Deathstroke vs Black Canary; 2x18 is 'Like A Finale' as Oliver Queen Rescues Thea [Watch Promo Video]

"Arrow" Season 2, Episode 18 airs Wednesday, Apr. 2 on The CW. Showrunner Marc Guggenheim promises big things. Oliver Queen aka The Arrow (Stephen Amell) gets vengeful. Meanwhile, Sara Lance aka Black Canary (Caity Lotz) may have to kill or be killed by Slade Wilson (Manu Bennett).

Spoiler alert: This feature contains spoilers on Arrow Season 2, Episode 18, titled "Deathstroke." The title says it all. Watch the sneak preview to this finale-like episode.

In Arrow Season 2, Episode 17 ("Birds of Prey"), Thea Queen is abducted by Slade Wilson. Oliver Queen makes sure Roy Harper (Colton Haynes) breaks up with Thea, and this is what happens next.

"Get Slade or get slayed," is the resonating message of The CW preview for Arrow Season 2, Episode 18, titled "Deathstroke." Does the "original" Black Canary get slayed (and Laurel takes her place)?

In this Arrow 2x18 sneak peek video featuring Arrow showrunner Marc Guggenheim, viewers are promised of a treatment similar to a season finale. Then Guggenheim says something about Laurel Lance (Katie Cassidy).

"Laurel will never be the same after this episode," said the Arrow executive producer. Could this be related to Black Canary? Laurel has "met" the Canary in "Birds of Prey." Will she find out the woman behind the mask that saved her?

"Team Arrow suffers a devastating loss as a result of this episode," Guggenheim noted. The show itself, Arrow, "will never be the same." Big words from the man who runs the DC comics-inspired show.

Guggenheim's quick mention of Laurel could mean anything - but it is likely to be a big thing in Arrow 2 x 18. Laurel might find out who The Arrow is. Oliver Queen may have to identify himself as the vigilante before his mother and Thea. Or, something bad could happen to Laurel's sister, Sara Lance.

Isabel Rochev (Summer Glau) is also in Arrow 2x18. She has more problems to throw in the Queens' already beleaguered world.

Where is Malcolm Merlyn (John Barrowman)? His daughter is in danger. Will he eventually work with Oliver Queen in Arrow Season 2 to make sure Thea remains safe from Deathstroke?

Arrow Season 2 takes a 2-week break after Episode 18. Bigger things are to happen in the final five episodes of the season. With Arrow Season 3 officially greenlit, production is expected to plant seeds for the next big chapter of this ever-evolving series.

WATCH: Arrow Season 2, Episode 18, titled 'Deathstroke' (The CW on YouTube)

Arrow Season 2, Episode 18, airs two weeks before the next new episode. "The Man Under the Hood" is the title of Arrow 2x19. It does sound like more people are going to find out that The Arrow and Oliver Queen are one and the same.

More TV Guide and Spoiler Features

'Arrow' Season 2, Episode 17 Spoilers: Black Canary vs Huntress on 'Birds of Prey' Thrill; Stephen Amell Teases 'Action, Action, Action!' [Watch Promo Video]
'Arrow' Season 2 Spoilers, Speculation: Oliver Queen vs Harley Quinn? Deadshot, Bronze Tiger, Shrapnel in New Episode [Watch Promo Video]