Tonight's episode of "The Flash," "King Shark" was one of the saddest episodes of the entire series. Not only was Barry being stalked by a "Jaws"-like metahuman, but he was dealing with the fallout of what happened on Earth-2. He, Cisco and Wells agreed to not tell any of their Earth-1 friends what happened on Earth-2, and throughout the entire episode it ate them up inside. Team Flash was also left reeling from the sudden death of Jay Garrick, whom Zoom pulled through the breach in the final moments of last week's episode. Caitlin in particular took Jay's death hard, and the whole team suffered at having to deal with the madness of Zoom again. John and Lyla Diggle also visited "The Flash" this week, to track down King Shark who was previously in the custody of A.R.G.U.S. The entire episode felt somber, and to make things worse, with the breaches permanently closed, there was nothing Barry could do to go back and protect Earth-2 from the wickedness of Zoom.

The first part of this episode should be called "What Happens on Earth-2 Stays on Earth-2," because right as Barry (Grant Gustin,) Cisco (Carlos Valdes,) and Harry (Tom Cavanagh) got back from Earth-2, they made a pact not to tell Caitlin (Danielle Panabaker,) Joe (Jesse L. Martin,) and Iris (Candice Patton) about their Earth-2 doubles. Instead they focused on the untimely death of Jay Garrick (Teddy Sears.) Jay's death hit the team hard, and considering he is such a huge part of the legacy of "The Flash" comics, his death will reverberate throughout the fans as well. Caitlin took his death the hardest, and she said what everyone was thinking, "No, not again." Caitlin lost Ronnie (Robbie Amell) twice, and now she's lost the man she loves again.

Because of Jay's death and what happened on Earth-2, Barry decided to run towards a distraction. In his voice over this week, he even wished for a metahuman to come cause trouble in Central City so that he could put his anger, his rage and focus on something else. His wish was answered in the shape of a giant man-shark: King Shark. King Shark was introduced in the fourth episode of this season, when Zoom sent him after Barry. In that episode, Harry Wells neutralized him. Turns out King Shark wasn't killed, but sent off to A.R.G.U.S. to be studied. This week, "Arrow's" Diggle (David Ramsey) and Lyla (Audrey Marie Anderson) were sent to check on the A.R.G.U.S. facility where King Shark was being held, and he escaped. Interestingly, it was revealed in this episode that Lyla was promoted to director of A.R.G.U.S., in the wake of Amanda Waller's death. Lyla was previously retired, but returned to clean up all the messes that Waller left behind, including the rogue metahuman experimentation programs. Diggle and Lyla tracked King Shark as far as Central City, and showed up at S.T.A.R. Labs to warn Team Flash. Surprisingly, Team Flash was actually looking forward to fighting a meta, especially Barry.

Harry and Jesse (Violett Beane) started working on a way to track King Shark, and Barry started looked for him at all the docks. Barry couldn't devote 100% of his attention to King Shark though, because Joe wanted him to spend some quality time with Wally (Keiynan Lonsdale.) Wally and Barry kept rubbing each other the wrong way, and when King Shark showed up at the West house, Barry had to run upstairs so he could put on The Flash suit. Wally saw this as Barry being cowardly, and even called him out on it. Because of this tension, Barry decided to finally tell Joe and Iris what happened on Earth-2. Iris was happy to discover she was a detective, like her dad, but Joe and Iris both got really quiet when Barry told them Joe was killed. The guilt that had been eating Barry upside was finally uncorked, and he was able to tell them how much regret he had about going over there and accidentally getting Joe-2 killed. Barry also shared his feelings of guilt with Diggle, who gave him the classic Diggle pep talk. He said, "You're doing what Oliver does. You're carrying the weight of the world on your shoulders. You gotta stop that man, it'll slow you down."

Cisco also eventually cracked and told Caitlin about her double as well, Killer Frost. Throughout the episode Caitlin was working harder and harder in the lab, and Cisco was getting increasingly worried that she was becoming cold in her heart. When he told her that her double was a metahuman villain named Killer Frost, Caitlin was surprised, but she assured Cisco that her determination to stay stone faced was in an effort to not let any emotions about Jay out, for fear that they would consume her. She had already lost Ronnie twice, and losing Jay made Caitlin afraid that if she even let a shred of emotion out, it would come pouring out of her and would never stop. Later on she even teased Cisco that she was Killer Frost, and that she "Hated the Name Caitlin." It terrified Cisco to think that his best friend could ever be a killer, but Caitlin reminded Cisco that she doesn't have metahuman DNA. It's possible that Cisco was worried about Caitlin becoming Killer Frost because ultimately he's worried he'll become like Reverb.

Breach! #TheFlash pic.twitter.com/yCNMbytyLM- The Flash (@CW_TheFlash) February 24, 2016

The episode concluded with a massive showdown between Barry and King Shark. King Shark refused to fall for the bait that Team Flash left him. Barry had to challenge King Shark head on, in the water. Barry was able to beat him by charging up the water around King Shark so fast, he could use the electricity to throw a massive bolt of lightning at him. King Shark went back to A.R.G.U.S., and Lyla promised to let his Earth-1 fiance help them find him a cure. Barry apologized to his team, taking the blame for opening up the portal between Earth-1 and Earth-2 when he went back in time to save his mom. He admitted he was at fault for giving Zoom access to this world, and that he was going to do something about it. Even though they closed all of the breaches to Earth-2, Barry was going to open one to get Zoom once and for all. The post credit scene of the episode, was Zoom, back in his lair, dragging the body of a dead Jay Garrick. The man in the iron mask looked terrified at what he was witnessing. Zoom then did what audiences have been wanting him to do for months, he took off his mask. To the surprise of many, the unmasked villain was Jay Garrick. He final words were, "Well this is a complication." A complication? What does that mean? That means there are three Jay Garricks -- possibly four if the man in the iron mask is Jay too. Is Zoom cloning himself? Was the Jay that he killed Everyman? At this point we still have no idea what's really going on, but for those of you who predicted Zoom was Jay Garrick/Hunter Zolomon, good job!

"The Flash" is on hiatus for the next three weeks, and returns to the CW Tuesday, March 22 at 8 p.m.