On this week's episode of "The Flash," Jesse Quick finally got to wear her new suit. With Wally's fears about not become a speedster (yet) quieted, Jesse and Wally were able to take their friendship and their relationship to the next level. Barry and Iris also began exploring new avenues of their relationship, but the "kissing" dynamics were a bit too awkward for Barry and Joe to overcome. Caitlin's Killer Frost powers began to manifest more fully this week, as she needed to use them (secretly) to save Barry's life. Cisco and Wells also tested out a fascinating experiment that led to the introduction of a brand new Doctor Wells. Two metahumans also plagued Central City this week -- Mirror Master and The Top -- as they recently searched for the missing-in-action Captain Cold. This week's episode was filled with more dating and more humor than former weeks -- it also included more science, with call-outs to worm holes (hello "Star Trek: Deep Space Nine,") Einstein-Rosen Bridges (hello "Thor,") and molecular deceleration (hello need for Killer Frost.) Mirror Master and The Top were both fun additions to the series this week -- hopefully they'll be back for a Rogues team-up in the future.

Mirror Mirror On the Wall, Who's the Rogue-est of Them All?

Tonight's episode -- "The New Rogues" -- kicked off with a flashback to the night the particle accelerator exploded. After two of Captain Cold's team members started spending money from a job they pulled, Cold decided to kill both Sam Scutter and his girlfriend Roslyn Dillon. Right as he was about the kill them the accelerator exploded, which knocked Roslyn to the ground. When she got up, Sam was gone and all that was left was the glass from a shattered mirror. Fast forward to present day, Sam found himself stuck inside that same mirror, with powers. After discovering his new Mirror Master powers, he broke Sam out of prison and together they decided to look for Snart -- to exact their revenge for his attempt at killing them all those years ago. Snart was nowhere to be found, so he and Roslyn, who also had powers, decided to become the new king and queen of Central City. The Flash and Jesse tried to stop them, but Sam trapped Barry inside a mirror with no way out. Roslyn, whom Cisco named The Top, was also able to get away when she zapped Jesse with vertigo. Barry was able to finally beat Mirror Master when he used a hologram of Snart in an old amusement park fun house.

The Race of Her Life

Jesse's training continued this week, which came with lessons in love, lessons in failing, and lessons in getting back up once she fell. Much like Barry's early training, more of what Jesse learned came not from her strengths, but her weaknesses. Jesse got her super suit this week, which looked amazing, and she even got to play sidekick when Barry tracked down Mirror Master and The Top. Unfortunately, when Barry told Jesse to wait for him on the ground, she raced up to where The Top was, who instantly whammied Jesse. She was so struck with vertigo that she fell off a high-rise building -- thankfully Barry was there to catch her. Embarrassed and dizzy, Jesse resolved to take off her super suit and forget about trying to be a hero. Thankfully Wally was there to encourage that making mistakes was important and that the speedforce gave her powers for a reason. When Jesse faced off against The Top again, she got the upper hand, and helped put The Top back in prison. Jesse also tried to move a little quickly with Wally, who initially pushed her away after she kissed him. He came around eventually, and the two cutely agreed to long distance date across the multiverse. It was refreshing to see Wally genuinely excited for Jesse, after being so downtrodden and broody last week. Jesse returned to Earth-2 at the end of the episode, alongside her father, the both of whom were excited to resume their metahuman fighting duties back home.

The Many Faces of Harrison Wells

Some of the funniest moments in this episode came from the witty banter between Harry and Cisco. Every week these two brilliant guys find ways to collaborate and solve impossible projects, all while quoting movies and naming metahumans. Their dynamic is special, but as Harry pointed out tonight, it was time for him and Jesse to return to Earth-2. With Harry leaving, both Cisco and Caitlin began to lament his absence, right along with the audience who would miss Tom Cavanagh. This prompted Harry to suggest a solution: import another Dr. Wells from one of the other Earths in the multiverse. After designing a riddle only another Wells could solve, three Wells called in with the answer. One was a cowboy, quite possibly a drunk cowboy, one was from the Steampunk era, and the third was a bright, charming Wells. While Harry was hesitant to be replaced, he finally conceded, and this new Wells -- HR -- slid across the multiverse (thanks to Vibe) and agreed to join the team.

The Future Mr. and Mrs. Allen

Last week on "The Flash," Barry and Iris tried going on a date -- two dates actually -- that were invariably interrupted. This week they decided to stay in, a la Netflix and chilling, where they could cuddle and bond without worrying about being called away. The difficulty they discovered in dating at home was the presence of Joe. Despite talking to Joe and saying he was comfortable with everything, not even Barry could avoid the awkward tension of kissing or flirting with Iris when Joe was around. This presented Barry with an opportunity that he addressed at the end of the episode: moving out and getting a place on his own. When Barry broached the idea to Joe, Joe didn't hesitate to show Barry the door, effectively saying "You grown," time to move out. While watching the West family bond every week at Joe's house, it will be a refreshing change to see Barry "grow up" and into his own apartment.

Caitlin Needs to "Let It Go"

Caitlin's transformation into Killer Frost is happening fast. On tonight's episode, Team Flash needed to build a machine cold enough to stop the molecules from moving inside a mirror so that Barry could escape. Cisco and Wells built a device that could do it, but it couldn't get cold enough. Caitlin, finding herself alone with the mirror, used her Frost powers to freeze the mirror and free Barry. While Caitlin assumed her secret was safe, Harry Wells told Cisco that their device did not freeze the mirror and that something -- or someone -- did. The final moments of the episode saw Caitlin at home taking a shower. At first, the water was running hot like it was supposed too, but all of a sudden an icy blast shot out of Caitlin's hands and froze the water. When she got out of the shower, her lips were blue and her hair had begun turning white. Terrified that she was becoming Killer Frost, she cut off the white parts of her hair and the episode ended. At some point she's not going to be able to hide her powers, and she's going to need Team Flash's help. Hopefully she can see how just like Cisco became Vibe and not Reverb, she doesn't have to become Killer Frost, she can become her own metahuman, with a heroic name.

Next week's episode is titled "Monster" and will introduce Caitlin's mother:

Desperate to understand what is happening to her, Caitlin (Danielle Panabaker) visits her mother, Dr. Tannhauser (guest star Susan Walters), a renowned biomedical researcher, in the hopes that her mother can provide some answers about Caitlin’s growing meta-human powers. However, when Dr. Tannhauser treats her daughter like a test subject, Caitlin grows cold and brings up past wounds causing the two to have a major blowout. Meanwhile, after a mysterious new meta-human attacks Central City, Barry (Grant Gustin) tries to convince Julian (Tom Felton) to let him assist on the case.

Starring Grant Gustin as the Scarlet Speedster, “The Flash” airs Tuesdays at 8 pm ET/PT on The CW. The series also stars Jesse L. Martin, Tom Cavanagh, Carlos Valdes, Candice Patton, Danielle Panabaker, Keiynan Lonsdale and more.