After going to the past, Barry talks to Harrison Wells about him time traveling and the consequences of changing the timeline. Meanwhile, the Flash learns that Captain Cold and Heat Wave have returned to Central City. This time Snart has brought along his baby sister Lisa aka Golden Glider to help wreak havoc on the city.
The group has to go on the offensive against a claim that Greendale graduated a dog; Abed creates an attack ad discounting the dog; Britta, after pooping her pants, connects with Elroy over the band “Natalie is Freezing;” Chang shoots a single person porn.
Detective Kevin Ryan is on the security detail of a charismatic congressman attending a charity event when shots suddenly ring out. Driven to apprehend the killer, Ryan must revisit the events that led up to the shooting, with the help of Castle and Beckett.
Jimmy shows Chuck that he’s willing to do almost anything to win a case, even if it means getting his hands dirty.
Marty gets into a conflict with Denna when he pitches the CEO of a fast-food chain; Roscoe’s business is exposed, which hurts his status and future at school; Doug and Clyde have different reactions to dating the same woman.
Alicia’s political future is on the line when Peter gives an interview that could influence voter turnout on Election Day. Meanwhile, a weekend getaway with Kurt and his affluent hunting buddies could lead Diane to a prosperous new client for the firm.
Still weighed down by his last meeting with Ra’s al Ghul, Oliver returns home to find a new villain and his crew has started terrorizing Starling City — Michael Amar, AKA Murmur, a man whose mouth has been sewn shut. Meanwhile, Laurel and Nyssa bond over their issues with their fathers and Nyssa makes Laurel an offer. Thea is forced to come to terms with her father after Oliver brings Malcom to the loft to recover, and Lance shuts out both Laurel and the Arrow.
Cal seeks revenge on Coulson by assembling a team of Super Villains to destroy S.H.I.E.L.D. Meanwhile, May calls on renowned Dr. Andrew Garner, her charismatic ex-husband, with a crisis that threatens to tear the team apart.
Mark Mardon aka The Weather Wizard appears in Central City intent on avenging his brother Clyde’s death, and sets his sights on Joe, who shot Clyde. When Mardon attacks Joe and Barry, Barry is able to super-speed them to safety but Mardon gets away. Barry warns Joe not to go after a meta-human alone but Joe doesn’t listen and ends up in grave danger. Meanwhile, Cisco looks into the night the team captured the Reverse Flash and realizes something doesn’t add up and begins to wonder whether Joe was right about Dr. Wells. Barry and Linda end up on an awkward double date with Eddie and Iris.
The Dean purchases a VR system for Greendale that could bankrupt the school, forcing Jeff to find the creator, Elroy Patashnik, to save them. After moving in with Annie and Abed, Britta finds out her parents have been paying her debts to her friends. Chang gets bitten by a cat.