We get the origins of how Agent LIberty came to be and we see the events of the past three season through his eyes. We learn that Agent Liberty is family man and National City University history professor Ben Lockwood.

But before that, we start the events after the last episode. With kyrptonite in the air, Supergirl is falling fast to the ground and if she hits the ground, Brainy tells Alex that the impact would kills her. Luckily, J'onn gets there in time to catch Supergirl. The two arrive at the DEO and Supergirl is immediately brought to a room to have a whole bunch of yellow sun pointed at her. In addition, they place Astra's lead shield on Supergirl's chest to see if it helps.

Supergirl -- "Man of Steel" -- Image Number: SPG403b_0120r.jpg -- Pictured: Sam Witwer as Ben Lockwood/Agent Liberty -- Photo: Bettina Strauss/The CW -- © 2018 The CW Network, LLC. All Rights Reserved.

We then go back in time to Liberty's origin story. The first event we see is Supergirl's message to the nation during the events of Project Myriad. In a house in National City, Peter Lockwood is seeing Supergirl's message and starts spewing anti-alien sentiment and tells his son, Ben, that his steel factory lost the Luthocorp contract. Peter is also sharing his views to Ben's son, George. Ben and his wife, Lydia, tries to be a voice of reason by seeing the alien side of things but it falls on deaf ears.

Ben drives his dad to his factory and soon sees that his factory workers are attacking alien warehouse workers for the Nth Steel factory. Ben tries to protect the alien workers but when one inadvertently impales him with one of this horns as a defence mechanism, this seems to be the start of his anti-alien sentiment..

As Ben recovers, he visits Lena at L Corp. to ask to get his dad's contract back but Lena says that she can't as Nth Steel is much better material for her products in the long run.

Afterwards, we see Ben giving a lecture that soon turns into a bit of anti-alien rhetoric after seeing that metal from his white board is made from Nth Steel. When Ben returns home, he learns that his dad had to close down his factory. We then see Queen Rhea give her broadcast and we learn that we are on the cusp of the Daxamite invasion.

As the Daxamite invasion is in full force, the Lockwood's decide to escape their home to safety. As the are leaving, J'onn crashes through their house with a Daxamite and the fight ends up burning down the Lockwood home.

The next time we see Ben is him visiting James' office presumably at the beginning of season 3 as we see Cat giving her presidential press conference. Ben wants to know why CatCo has not covered the impact of the Daxamite invasion on regular folks. James says that CatCo has and that their coverage won a Pulitzer but Ben thinks that CatCo only covered it once and believes it should be ongoing. Not hearing what he wanted to hear, Ben leaves in a huff.

Supergirl -- "Man of Steel" -- Image Number: SPG403_Still_2.jpg -- Pictured (L-R): Sam Witwer as Ben Lockwood/Agent Liberty and Melissa Benoist as Kara/Supergirl -- Photo: The CW -- © 2018 The CW Network, LLC. All Rights Reserved.

We fast forward to events of 6 months ago. Ben is giving a lecture but this time his anti-alien rhetoric has gotten worse to the point where alien students and non-alien students have walked out of his class. Dean Warren speaks to him and pretty much fires him. Ben believes an alien student complained about him and goes to confront her in the alien bar. Luckily, Kara is there for karaoke night and stops the confrontation from getting worse.

Supergirl -- "Man of Steel" -- Image Number: SPG403a_0095r.jpg -- Pictured (L-R): Sam Witwer as Ben Lockwood/Agent Liberty and Rhona Mitra as Mercy Graves -- Photo: Bettina Strauss/The CW -- © 2018 The CW Network, LLC. All Rights Reserved.

With no job, we see Ben accosting people on the streets with pamphlets with his anti-alien speech. The only person that takes one of this pamphlets is Otis Graves. We soon see that this was taking place during the season 3 finale when Selina did Genesis. Ben gets a call from Lydia about his dad. Ben rushes to the closed down Lockwood Steel factory to see that Pete is trapped under a steel beam. Ben tries to free him but Pete says he came to the factory to die. Before Pete dies, he tells Ben to stand up for the humans of Earth.

After, Pete's funeral, Ben and some former steel workers, go to the Nth Steel factory to burn it down. An employee stumbles out and when him image inducer fails, the men see it is an alien, the same alien that accidentally impaled Ben. This causes Ben to beat the alien to death.

As we inch towards the events of season 4 so far, Ben is using oration skills to talk more about his anti-alien rhetoric and learns that Dean Warren has lost her home because of Genesis and seems to get her to join his cause. Ben is walking along the street when Mercy approaches him in her limo and gets him to talk to her inside. Mercy tells Ben that he has been a bit sloppy with his attacks against aliens. Ben thinks Mercy is going to arrest him but she actually wants to work together and gives him his Agent Liberty suit and his first target: Fiona.

We then start back up to the events of today. Brainy says that there really is nothing they can do to help Supergirl but Alex won't accept defeat. Lena is called in and brings a device that incases Supergirl in a new suit that will help protect her from the kryptonite in the atmosphere giving the DEO time to figure something more permanent out.

Meanwhile, at the old Lockwood Steel factory, Mercy wants to kill Jansen but Ben stops her as they can use him to break into the DEO.