'Flash' is possibly airing the most action-packed episode this season on Tuesday night, and it appears that 'Flash' and 'Arrow' fans are in for a surprise when another crossover happens tonight. Apparently, Dr. Wells or Eobard Thawne is up to something and it's up to Barry and his friends to contain whatever madness he's planning on doing. Don't miss when your favorite heroes unite. Tune in on The CW at 8 p.m. EST or simply watch 'Flash' season 1 episode 22 stream using the free online stream link at the end of this post.

Note: This feature contains spoilers on the upcoming episode of 'The Flash.' Kindly read at your own risk.

The penultimate episode of CW's 'Flash' is going to be epic after last week's show where it was revealed that the thief was no other than General Wade Eiling, who was unfortunately under the power of S.T.A.R. Labs experimental subject Grodd. It was actually Dr. Wells plan to distract his team so he could get enough time to plot an surprise attack. Elsewhere, Iris confronted Barry Allen about his alter-ego. Amid the tension between them, Barry promised Iris that he would bring Eddie back. This week, Barry will get reinforcement in the persons of Firestorm and Arrow, along with an old foe, Captain Cold. But are they enough to take on Dr. Wells' villainous identity? Find out by tuning in on The CW at 8 p.m. EST or by simply watching 'Flash' season 1 episode 22 online using the free online stream link below.

Meanwhile, actor Tom Cavanagh, who plays Dr. Wells/Eobard recently gushed about the upcoming episode where his character is to face the trio of superheroes. "It's a relief that it wasn't a 'handsome-off,'" he said. "If it had been a handsome-off, it would've been a miserable defeat right off the bat for me. Those are three very good-looking gentlemen right there that I was facing off with. When you do a movie, you spend two hours moving the narrative along to the big culmination or cumulative scenes. When you do a television show, instead of two hours, you're doing 20-plus hours. But you know you're headed towards a showdown - if you're doing it right - of some sort."

Cavanagh then added: "One of the most gratifying parts is that we feel we've earned it. We've put 20 hours' worth - in the case of Stephen, three seasons-plus - of effort into getting people to understand these characters, to identify with these characters, to know their world. And so, when you finally put in all that time, and then you bring the showdown, it's a lot better than having two gun fighters face off on an empty street in the opening minutes of your show." Watch 'Flash' season 1 episode 22 stream through the free online stream link at the bottom.

The official synopsis of 'Flash' season 1 episode 22 reads: "As Wells (Tom Cavanagh) once again gets the upper hand on the S.T.A.R. Labs team, Barry (Grant Gustin) is going to realize he needs to make a big move and reaches out to an old foe, Captain Cold (guest star Wentworth Miller), for help."

"Joe (Jesse L. Martin) and Caitlin (Danielle Panabaker) will warn Barry that Cold can't be trusted. True to form, Cold will have his own agenda that involves the meta-humans trapped in the containment cells. As things seem to be going from bad to worse, The Flash will get reinforcements - Arrow (guest star Stephen Amell) and Firestorm (guest star Robbie Amell)."

"Rogue Air" is set to air this Tuesday night at 8/7c. Watch 'Flash' season 1 episode 22 stream using this free online stream link here.