On tonight's episode of "Arrow" the team was in a race against time before Damien Darhk could set off a nuclear weapon. With the Rubicon codes in Darhk's possession, it was only a matter of time before nuclear missile silos all over the world began opening up. In order to stop the launch codes, Felicity recruited the help of her father, returning guest star Tom Amandes. Diggle continued to deal with the aftermath of killing his brother, while he and Oliver tracked down Darhk's "Nexus of Power" room. Thea had her own demons to battle this week, as she was trapped inside the underground city Darhk built for his new world order. This episode also featured the return of Anarky, whose quest for vengeance against Darhk led him right to Thea.

Picking up where last week's episode "Genesis" left off, "Monument Point" began with Lyla (Audrey Marie Anderson,) Diggle (David Ramsey,) Oliver (Stephen Amell,) and Felicity (Emily Bett Rickards) figuring out how to stop Darhk (Neal McDonough) from launching the codes. Felicity knew she can hack her way to a solution, but not without her father, The Noah Cutter (Tom Amandes.) In order for Felicity to find her father, she needed to ask her mother about their history together. When Felicity discovered he was staying in a cabin, Team Arrow want to find him. When they got to the cabin, they ran into what Felicity referred to as "Last year's greatest hits," AKA two of the villains they beat in season three: Murmur and Brick. Team Arrow was able to beat Darhk's men and rescued Noah just before they tried to killed him.

With Noah on her side, all Felicity needed to stop the nuclear launch was a piece of equipment from Palmer Technologies. When she arrived at work to grab the tech, she was forcefully escorted out of the building by security. As it turned out, Felicity was fired as CEO of Palmer Technologies by the company's board of directors. This was a huge blow to Felicity, who had been running Palmer Tech since Ray Palmer (Brandon Routh) was pronounced dead during the season three finale. With Felicity fired from Palmer Tech, she and her father were forced to break into the building to steal it. With Felicity no longer running Palmer Tech, that could leave the door wide open for Ray to come back after he's done gallivanting on "Legends of Tomorrow." It also leaves the door open for a new CEO, possibly the mysterious new character being cast for "Arrow" season five. With the tech in hand, Felicity and her father were able to stop all of the launch codes, except one. One nuke was successfully launched by Darhk and was heading towards a town called Monument Point. In a tragic move Felicity was able to reroute the nuke to a town called Havenrock. The bomb still detonated and hundreds of thousands of people died. While Felicity didn't launch the nuke herself, you could see the guilt all over her face when she realized she caused the death of thousands.

While Team Arrow was fighting and stopping a global nuclear holocaust, Thea (Willa Holland) was trapped inside "Noah's Ark" town with her father Malcolm (John Barrowman.) She tried to convince her father that he was crazy for thinking it was OK to blow up the world, but he believed the world was crazy enough to deserve to be destroyed. While they were in the Ark they had to face off against a familiar foe -- Anarky -- guest star Alexander Calvert. Anarky claimed he had a special bond with Thea, since she made him who he was. While Thea wasn't his target (he was after Darhk) she did have to fight him. While the episode didn't make it clear, it looked like Anarky was either dead or passed out in the final moments of their battle.

The episode concluded with Oliver and Diggle tracking the magical lay lines to Darhk's Nexus Chamber where he was charging himself up with all of the lives he just claimed. While the episode ended in that moment, it's hard to say how Oliver and Diggle will be allowed to leave that chamber next week alive. Captain Lance (Paul Blackthorne) also made an important decision this week, as Felicity's mom Donna (Charlotte Ross) encouraged him to be honest about knowing Laurel was the Black Canary, and not lying to the SCPD in order to keep his badge. With Lance possibly losing his badge for good and Felicity being removed as CEO of Palmer Tech (and sort of being responsible for the death of everyone in Havenrock) this season could leave the cast in very unpredictable positions for season five.

Next week's episode of "Arrow -- "Lost in the Flood" -- features Noah's continued work with Team Arrow. Oliver also finds a way into the Ark city to rescue Thea. Unfortunately it appears as though Thea may be under the influence of Darhk's ghost medicine, as she and Oliver can be seen facing off in the trailer above.

"Lost in the Flood" -- (8:00-9:00 p.m. ET) OLIVER FIGHTS FOR THEA; DONNA SMOAK FACES OFF WITH NOAH KUTTLER -- Following the shocking events in the previous episode, Oliver (Stephen Amell) and Diggle (David Ramsey) race to rescue Thea (Willa Holland), while Felicity (Emily Bett Rickards), Curtis (Echo Kellum) and Noah (guest star Tom Amandes) join together to stop Darhk (guest star Neal McDonough). Glen Winter directed the episode written by Brian Ford Sullivan & Oscar Balderrama (#422). Original airdate 5/18/2016.

"Lost in the Flood" airs Wednesday May 18 at 8 p.m. on The CW.