On Tuesday night's episode of "The Flash", Barry Allen came face to face with another speedster, Jay Garrick -- DC Comics' original Flash from the Golden Age. Normally, the arrival of another speedster would pique Barry's interest, but after his battle with the Reverse Flash -- the man who killed his mother and the archvillain of last season -- Barry is extremely distrusting of anyone who claims to have Flash-like powers. The title of this episode, the introduction of Jay Garrick, even the concept of multiple Earths all harken back to 1961's "The Flash" #123, the famous "Flash of Two Worlds" story by Gardner Fox and Carmine Infantino. Tonight's episode recreated Barry and Jay's classic meetup, but instead of Barry traveling to Jay's world as he did in the comic, Jay has traveled to Barry's world. And Jay's arrival couldn't have come at a better time, now that Barry is being hunted by Jay's greatest adversary: Zoom.

At the beginning of this episode, Jay Garrick startles the Flash team when he enters S.T.A.R. Labs out of nowhere. Detective West pulls a gun on Jay, but lowers it as Jay begins to tell the story of where he came from. According to Jay, he was a speedster, like Barry, who used his superspeed to protect his city. Before Jay became his world's version of The Flash, he was a scientist. During the last two years as a speedster Jay encountered a metahuman named Zoom, even faster than himself. Zoom almost killed Garrick, before a portal opened up and Jay passed through it -- but when Jay arrived in Central City, he no longer had his super-speed. Barry, who doubts Jay's story, orders Caitlin to run tests on him. Caitlin and Jay share a moment together during these sessions, which is a good sign she is slowly getting over the death of her husband Ronnie Raymond.

While Barry remains skeptical of Jay's story, Dr. Stein runs with it. Stein beings explaining the "Many Different Worlds" theory, which posits the idea that different worlds can interact with each other across parallel, or multiple, universes. Stein even uses the term "Multiverse," a word with which many DC Comics fans are familiar. Stein continues to describe these different worlds, labeling their world "Earth-1" and Jay's world "Earth-2." Stein also determines that if Jay is telling the truth, and the worlds are intersecting through the portals that were opened up by the singularity, and that the portals, the breaches, must be found and closed as soon as possible.

Detective West, overwhelmed by the idea of doppelgangers and multiple Earths, heads back to the station where he is met by an eager beat cop, Patty Spivot, played by Shantel Vansanten ("One Tree Hill"). Patty wants to join the anti-metahuman task force, but Detective West denies her request. Later that evening Barry gets a call about a fire in Central City. He is quickly able to extinguish the fire, but once there he is met by a metahuman, a man who can turn into sand. Detective West meets Barry at the scene later, to see if they can find any clues on the identity of the sandy suspect. Patty Spivot arrives at the scene too, and proceeds to fangirl all over Barry -- not for being The Flash, but for his crime scene analyst skills. Patty is a lot like "Arrows'" Felicity, as teased by "The Flash" writers over the summer.

Back at S.T.A.R. Labs, Cisco, Barry, Iris and Caitlin analyze the sandy material Spivot found at the crime scene. Everyone thinks it's sand, but Jay explains that it's actually a metahuman's tissue. Jay knows this because he fought the Sand Demon on his earth. Cisco gets a little sassy with Jay because he loves to be the one naming metahumans -- but lets it slide since the name is so good. Since Jay has defeated this metahuman before, he offers to help Barry -- but Barry is still too closed off to let Jay help him.

Cisco and Stein continue to study the multiple worlds theory in an effort to find the portal breaches. Cisco delivers the best line of the episode when he sees Stein writing all over the chalkboards at S.T.A.R. Labs: "Beautiful Mind, I think you need to take a breather." Stein discovers a way to test his theory and leaves Cisco, who begins to run a test on the sand material. When Cisco touches it, his metahuman power is triggered, and he sees Sand Demon take down Barry. Cisco is left stunned because he still doesn't understand what is happening to him.

Detective West tracks down the suspect with the help of Patty, who proves to be worthy to be on the task force. While Joe interrogates him, Patty and Barry share a moment, quoting Monty Python's classic questions on the bridge game. The suspect claims he is innocent and Joe confirms that he was locked up in Black Gate Penitentiary during the particle accelerator explosion. That means only one thing: Sand Demon is from Jay's Earth-2. Even though all the facts point to Jay's honesty, Barry still refuses to believe him. Iris calls Barry out on his lack of trust: "Not everyone is Harrison Wells."

The Earth-2 Sand Demon gets to Patty, and Barry, having been encouraged by Iris, asks Jay for help. Cisco also tries to assist, by tapping into his powers to see where Sand Demon is holding Patty. Both Cisco and Barry are successful and they team up with Jay to take down Sand Demon. They even give Jay his hat back, the one that came out of the portal in the season one finale. Jay Garrick and Barry Allen team up and rescue Patty, as Barry taps into the Speed Force and releases a pulse of lightning and takes down Sand Demon. Barry didn't know he could even do that, but through Jay's coaching, Barry's learning a lot about his powers. After their victory, Jay and Barry reconcile and tease each other about their respective Flash nicknames: "Scarlet Speedster" and "Crimson Comet." Barry finally asks Jay about Zoom. According to Jay, Zoom is an unknown force who has made it his life's goal to kill speedsters.

The episode concludes with Patty revealing her true motivation for joining the task force: Her father was killed by the Weather Wizard brothers. Right after Joe accepts Patty onto the team and promotes her to Detective, a woman shows up at the police department. The women? Iris' mother, played by Vanessa A. Williams.

Lastly, Stein confronts Cisco about his hunches, who comes clean about his ability to perceive times and futures. Sadly, Cisco doesn't want anyone to know about his power, because of what Wells' told him. As they discuss Cisco's "vibes," they're alerted to the success of their breach detection. Jay was right, there are 52 breaches in Central City. Right at this moment, Dr. Stein collapses on the floor, incapacitated. The last thing we see is the future, or an alternate earth, with a group of children touring S.T.A.R. Labs. The children are surprised when the founder and "savior of central city" steps out of the elevator of the lab -- none other than Harrison Wells.

Jay Garrick, Zoom, Earth-2, Cisco's "Vibe" powers -- everything in this episode paid true homage to the great legacy of "The Flash" comics. Not only did the episode introduce the multiverse and tease something akin to The New 52, it gave a shout out to "Arrow," as it showed the clip of Oliver's Green Arrow broadcast from last week. Plus, the episode introduced Iris' mom and resurrected Harrison Wells, in a sense. With all this happening only two episodes in, it looks like viewers are in for quite a ride this season.