'Arrow' season 5 episode 8 spoilers: Oliver weds Laurel in 100th episode; new crossover trailer reveals alien threat

"Arrow" is about to hit a milestone episode and it will do so in style. Not only will the 100th episode fall right in with The CW's upcoming "Heroes v Aliens" crossover, it will also feature a dream wedding that could've been but never was.

The upcoming eighth episode of "Arrow" season 5 is supposedly the third installment to the four-way superhero crossover happening on The CW next week. But the official press release for the episode seems to hint at an entirely different timeline. In this reality, Oliver (Stephen Amell) never boarded his father's yacht, The Queen's Gambit; he was never caught on a shipwreck that got him stranded in the island of Lian Yu; and most importantly he never became Green Arrow.

But no matter how perfect his life may be, Oliver will soon realize that something is amiss, and the little imperfections he will notice along the way will lead him to question this seemingly fabricated reality he is stuck in.

In an exclusive interview with TV Line, actor Amell described the unexpected turn of events as a "radical departure" from the show's usual plotlines. He also shared that the time aberrations in episode 8 is neither a flashback nor a flash forward, but is "something else entirely."

Could Oliver be dreaming of a life he had in a parallel universe? If this is the case, what could be causing it? How will this storyline tie up with the "Heroes v Aliens" crossover?

However way Oliver's perfect life will end, it gives the aggrieved son, lover, and friend a chance to say the goodbyes he never got to say to the people he lost, and thus find the closure he needs to finally start healing.

Meanwhile, The CW has just released a found-footage type trailer for "Legends of Tomorrow" that will give fans a glimpse of the threat that is about to bring the Earth's superheroes together in an epic battle against their biggest adversary yet: the Dominators.

The "Heroes v Aliens" crossover will start next week in "Supegirl" on Monday, Nov. 28 and continues in "The Flash" on Tuesday, Nov. 29, "Arrow" on Wednesday, Nov. 30, and "Legends of Tomorrow" on Thursday, Dec. 1. All shows will air at 8 p.m. EST on The CW.