Flash season 2 episode 13
The Flash and Cisco with Earth 2's Iris West in The Flash season 2 episode13The CW

Ever since the concept of a multiple-universe was introduced in The Flash, fans were eagerly awaited for the moment when Barry Allen would crossover to Earth 2. Their wish was finally granted in this Monday's episode titled, Welcome To Earth 2, when Barry, Cisco Ramone and Harrison Wells took a trip to Earth 2 to save Wells' daughter Jesse from Zoom.

Here are a few shocking moments from episode 13 [Warning: Spoilers ahead]

1. Although The Flash and Supergirl crossover was confirmed, fans did not expect Kara to show up on the show this early. While travelling through time, and passing via the speed canon, fans got a glimpse of Kara aka Supergirl.

2. Barry and Cisco are trapped in Earth 2 as the speed canon collapsed after the heroes travelled through it. Jay Garrick told Joe, "With the rest of the breaches closed, the energy surged to the last remaining breach must have destabilised it." This means, as long as the speed canon is unstable, Barry and Cisco will be trapped on the other side.

3. Barry's doppelganger is a CSI agent in Earth 2. The two come face-to-face for the first time and actor Grant Gustin has nailed it with an outstanding performance of both characters. In the scene Barry from Earth 2, flips out after meeting Harrison Wells. Also, Barry from Earth 1 tasers his doppelganger and knocks him out, to take his place and find Zoom.

4. Iris West is a detective in Earth 2 and Allen and Iris are married. This is a victory moment for all West-Allen fans.

Flash season 2 episode 13
Robbie Amell as Deathstorm and Danielle Panabaker as Killer Frost in The Flash season 2 episode 13The CW

5. The good doctor from Earth 1 is Killer Frost, who works for Zoom. She kills people by kissing them and freezing them to death. Earth 1's Ronnie Raymond is alive in Earth 2 and goes by the name Deathstorm, as he kills people with his fiery superpower. Frost and Deathstorm are a couple aka the fire and ice couple, and their hobby is to kill people.

6. Barry's mother Nora Allen is alive in this universe, and Barry calls her up and breaks down on hearing his mother's voice.

Flash season 2 episode 13
Barry Allen from Earth 2 with Iris West and Joe West in The Flash season 2 episode 13The CW

7. Joe West is a singer in Earth 2 and he is not a fan of Barry Allen. Barry and Joe are like father-son in Earth 1, but their dynamic is different in the other universe. He blames Barry for making Iris a police officer thereby jeopardising her safety and calls Barry selfish.

8. Back in earth 1, Jay Garrick tells Caitlin Snow that he took velocity 6, and he has fallen sick. Garrick admits he took the drug, and there were some unforeseen side effects. Snow figures out that Zoom never took his speed, the drug is what was making him sick, and vows to make an antidote to save him.

9. Fight scenes between Frost, Deathstorm and Flash have been amazing. Barry calls the Killer Frost by her real name Caitlin, but it did not bode well for them and Joe loses his life in the process.

10. Barry and Cisco along with Iris set a trap for the Killer Frost and Deathstorm. During which they learn that Cisco has an evil dopplelganger, who calls himself, Reverb. Killer Frost and Deathstorm work for the evil Cisco, who then reports them to Zoom. Also, Reverb gives Cisco a chance to be like him.

11. The episode ends with bad news as Zoom now has The Flash, and the speed demon kills Reverb and Deathstorm for not following his orders to bring him the Speedster alive. He locks Barry up in his cage, where he meets Jesse.

If you missed the episode, click here to watch the episode online on The CW website in the US.