James falls in deeper with the Children of Liberty in his efforts to meet Agent Liberty. Meanwhile, Supergirl and Manchester Black follow a lead on Agent Liberty's location, but things take a dark turn. Lena kicks off her first set of trials.
Nia has a powerful dream about Agent Liberty but refuses to look at it as a prophetic dream and pushes it aside. After noticing something is bothering Nia, Kara enlists Brainy's help, and the two try to persuade Nia to embrace her destiny. Meanwhile, Manchester Black pays Ben Lockwood a menacing visit.
Colonel Haley is upset after Supergirl responds to a distress call from a Navy ship that turned out to be a deadly alien attack. Colonel Haley reclaims the site as DEO territory and demands that Supergirl step aside. After Supergirl refuses to be told what to do, Haley refocuses her energy on finding out Supergirl's true identity and begins to interrogate all DEO agents, including Alex. Meanwhile, Brainiac-5 tries to persuade Nia to embrace her superpowers but she misinterprets his motives.
Kara joins Nia on a trip to Nia's hometown to visit her family during the town's annual Harvest Festival. While home, Nia's mother encourages her daughter to embrace her destiny. Meanwhile, Alex deals with a street drug that is turning people violent and giving them temporary superpowers.
With his P.I. shingle newly hung outside his office, J'onn welcomes new clients. Trying to take her mind off what happened at the DEO, Kara decides to team up with J'onn on his latest assignment, which unfortunately ends up tying directly into Alex's current investigation that involves the villain Menagerie. Meanwhile, Lena shares some news with James, but his reaction isn't what she expected. Nia invites Brainy to her Valentine's Day party.
When Lockwood organizes a rally, the aliens decide to peacefully protest; Brainiac and J'onn join the alien march, while Supergirl and Dreamer patrol to keep everyone safe; Hayley assigns Alex a job that clashes with her beliefs.
Secretly furloughed from prison due to failing health, Lex Luthor visits his sister Lena to seek her help finding a cure. Savvy as ever, Lena is suspicious of Lex's motives, but when she's faced with a life and death situation, she must decide how she truly feels about her brother. Meanwhile, Supergirl and J'onn face off against Manchester Black. James' sister Kelly comes to town.
Kara and Lena head to Stryker's Island to find clues that may help defeat Lex; Kelly encourages James to confide in someone about his PTSD; Alex faces off against Ben Lockwood when he takes powerful weapons from the DEO to hunt Supergirl.
Kara and Lena head to Kaznia to hunt down Lex. However, Eve Tessmacher sets a trap for the duo that could ultimately reveal that Kara is Supergirl. Meanwhile, Alex gets a long-awaited phone call, James practices using his powers, and Ben Lockwood takes a dangerous stand inside the DEO.