This week's episode of "The Flash" covered a lot of ground. The fate of Wally West was revealed, as was Alchemy's true identity. More of Barry's secrets about Flashpoint were uncovered, including the death of Cisco's brother Dante. Caitlin fought against the rising killer within, as she sought to understand and control her powers. Julian Albert got caught in Caitlin's cross hairs, which led to an unusual decision on Barry's part. The God of Speed was also revealed this week, as a dangerous new speedster named Savitar. Barry also had to experience the highs and lows, the regrets and triumphs of having powers, and knowing when to use them. With Alchemy revealed and the true Season 3 villain on the loose, this season answered many questions while setting up a dozen more. Let's jump into the breakdown of the Kevin Smith-directed episode,  "Killer Frost."

Beware the Frozen Heart

Caitlin's journey was front and center this week as she dealt with the growing nature of her powers. For the last few weeks she has had them under her control, but when Savitar almost killed Barry, Caitlin needed to tap into those powers to save him. Rescuing Barry demonstrated that her powers could be used for heroic actions, but her inability to control them backfired on her. When Joe was interrogating one of Alchemy's followers, Caitlin lied to Joe to get access to the man. She then kidnapped Julian Albert (Tom Felton) to use him to get to Alchemy. This put her directly in Barry's cross hairs, who tried to get to her before the police. Caitlin stabbed Barry in the leg with an icicle and tracked down another Alchemy follower. This follower told her that Savitar was God and that a terrible future was coming, with Caitlin reigning as Killer Frost. Caitlin almost killed him but was interrupted by Barry and Cisco. The three friends fought in the streets, with Cisco taking Caitlin out just as she gave Barry the frozen kiss of death. Cisco was able to put her into the pipeline at S.T.A.R. Labs, where she tormented Barry and the team with accusations of hatred and betrayal. Barry knew that something was influencing Caitlin, so he tested her resolve to see if she was still in there. Barry told Caitlin to "become the killer" she was professing to be and in that moment, the real Caitlin came back into control because the real Caitlin could never kill Barry.

It's All Barry's Fault

When Caitlin was in the pipeline, she accused Barry of some pretty wretched things. She blamed him for Ronnie's death, for Eddie's death, for Dante's death, even for her becoming Killer Frost. She condemned his optimism, his ability to trust that everything is going to be OK, when nothing in her life was OK. While this was Killer Frost talking and not Caitlin, those thoughts must have been in Caitlin's mind somewhere. Everything she said was true -- Barry could be blamed for a lot of things -- but as HR said to Joe this week -- Barry's greatest strength is not his speed but his hope. Barry's hope was challenged a great deal in this episode, especially when he felt he was losing Caitlin to Frost. Iris was his greatest encourager this week. She helped him find his sense of heroism and optimism again, even when Caitlin seemed like a lost cause. When he challenged Caitlin to kill him, he was drawing on his inner hope, and that is what saved her life. He was also drawing on his intense love for his friends when he agreed to resign from the CCPD. Barry chose to keep Caitlin's metahuman identity safe from Detective Patterson (guest star Greg Grunberg) and resigned from his job.

Alchemy Revealed

After Barry agreed to resign, Julian heard a voice in his mind. At first, it sounded like Alchemy's voice, like Alchemy was calling to him the way he called to Wally. Instead, the voice was Savitar, who was calling to Julian to become Alchemy -- pulling a "join me and together we will rule the galaxy" Darth Vader moment. Despite being injured from his run in with Caitlin, he made it back to the CCPD lab and took out the Alchemy mask. While no motivations have been revealed for Julian taking on such a dark disguise, the episode did reveal that Savitar was pretending to be a god. So far Savitar is using Alchemy's ability to turn people into metas to join some kind of team. Savitar was clearly faster than Barry this week -- he was even faster than Zoom and the Reverse Flash, but to what purpose? Hopefully, Alchemy and Savitar's full intentions will be revealed soon.

Say Hello to Kid Flash

The fate of Wally West was also revealed tonight. After being cocooned inside of a transformative husk and broken out by his dad, Wally emerged as a speedster. When his body wasn't moving in the correct timing as his brain, he erratically ran back to his childhood home in Keystone City. Caitlin was able to help his body align with the changes and after some training with Barry, he felt electrified and alive. Now that Cisco, Caitlin, and Wally are speedsters, it's beginning to look like Barry is assembling a superteam, which is happening just in time for the DC CW crossover.

Arrowverse Team Up

Next week "The Flash" will continue the night crossover. Barry will have retrieve Supergirl from her Earth to help Team Flash, Team Arrow, and the Legends fight an invading alien force called the Dominators.

IT’S HEROES VS. ALIENS IN THIS EPIC CROSSOVER EVENT — When aliens called the Dominators attack Central City, Barry (Grant Gustin) speeds over to Star City to ask the Green Arrow (guest star Stephen Amell) for help in stopping them. Realizing the battle against the Dominators is bigger than they thought, they track down the Legends of Tomorrow, and Barry and Cisco (Carlos Valdes) create a breach to bring back a secret weapon – Supergirl (guest star Melissa Benoist). Once all of the super friends are assembled, they come up with a plan to attack but a shocking secret related to Flashpoint is revealed and suddenly no one is sure who they can trust. Meanwhile, Wally (Keiynan Lonsdale) wants to join the battle against the aliens but Iris (Candice Patton) tells him he’s not ready. Dermott Downs directed the episode with story by Greg Berlanti & Andrew Kreisberg and teleplay by Aaron Helbing & Todd Helbing (#308). Original airdate 11/29/2016.

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.