After finding out the identity of Agent of Liberty, Manchester Black invited himself over to tea at the Lockwood home pretending to be Ben's former college buddy.
Initially, Lockwood didn't know what Manchester wanted with him until he revealed that Lockwood killed the love of his life, Fiona.
Black's plan was simple: make Ben suffer the way he had first by killing his wife, Linda, and then killing him while he's wearing his Agent of Liberty costume.
However, everyone was determined to stop him.
J'onn kept trying to locate Black by reaching out and talking some sense into him.
His lectures came at inopportune times and fell on deaf ears as Manchester had nothing left to lose.
Meanwhile, Kara teamed up with Nia and Brainy to track down the Agent of Liberty after Nia reported terrible nightmares about him.
Brainy tried his best to refrain from upsetting the time-space continuum, however, he did disclose that he's familiar with Nia in the 31st Century.
He also told Kara that she could lead them to the Agent of Liberty by exploring her nightmares, so that's exactly what they did.
Of course, that was after Nia confessed to being an alien from the planet Naltor in which generations of women experienced visions and dreams of the future.
Once she was able to let the visions in, she pulled a location for the upcoming attack.
At the site, Kara decided the best way to find the Agent of Liberty was by allowing themselves to get kidnapped by his "children" and their alien sniffing dogs.
They found themselves in an abandoned warehouse which Kara found out belonged to the Lockwood family.
After Brainy confirmed that Lockwood lost everything when the terraforming began, she knew he had to be their masked villain.
Alex confirmed it to be true, but when Supergirl arrived at Lockwood's home, she found out that Manchester beat her to the punch.
When she attempted to stop Manchester at the factory, he immobilized her by dumping Nth Metal on her.
Determined to free herself, she used all her strength to fly up into the air, lifting the factory and shattering the metal.
She saved both Ben and his wife, but when the cops came to arrest him, he blamed the whole situation on the aliens who were trying to harm his family.
He even openly questioned Supergirls identity which led President Baker to order more transparency from the DEO.
Part of that included revealing Supergirl's real identity, which didn't sit well with her.
When she refused to comply, President Baker dismissed her from her duties.
The final minutes of the episode teased the three-night crossover, Elseworlds, taking us to Earth-90 for a confrontation between the original Flash and The Monitor.