The adventures of Superman's cousin in her own superhero career.
Diving back into reporting, Kara welcomes a new cub reporter to CatCo. Meanwhile, James and Lena argue about James' impending indictment for acting as the vigilante Guardian, while Alex and Brainy struggle to get in sync at the DEO. Supergirl is called in
Supergirl must work with J'onn to contain the chaos resulting from Myr'nn's psychic disturbances at the DEO; Mon-El teaches Kara fighting techniques he learned in the future for battling Worldkillers.
Following the death of his father, Winn must work with his estranged mother to stop a copycat Toyman.
The DEO captures another Worldkiller, who escapes and attacks the city's subway tunnels
Morgan Edge accuses Lena of plotting an attempt on his life and Kara steps in to help her.
Supergirl and Saturn Girl recruit Livewire and Psi for a mission to recover a prisoner from Fort Rozz who knows how to defeat Reign.
Supergirl remains in a dreamlike state after sustaining injuries from Reign, so Mon-El recruits Brainiac-5, a member of the Legion of Superheroes, to bring her back.
Supergirl traces the origins of a mysterious symbol to an ancient prophecy and the mark of the World Killer, Reign.
The gang comes together for Barry and Iris's wedding, but the ceremony is crashed by villains from Earth-X.
Kara investigates when an alien ship lands deep underwater beneath National City; Hank attempts to bond with his father; Samantha looks to her estranged mother for answers.
Kara and Alex head home to Midvale for a little R&R. While there, Kara recalls a painful memory of a childhood friend's death and how that traumatic experience brought the Danver sisters closer together.
Morgan Edge blames Lena for children getting sick from lead poisoning.
Kara investigates a secretive new group whose leader, Thomas Coville, has a mysterious connection to Supergirl. Meanwhile, Samantha feels like she's letting Ruby down, and J'onn confesses an old secret.
Maggie reaches out to her estranged father when Eliza throws her and Alex a wedding shower, while Supergirl joins J'onn on a personal mission.
A thief with psychic powers attacks National City and proves to be a formidable opponent for Supergirl.
Kara deals with the loss on Mon-El by focusing her energy on being Supergirl and concentrating on a mysterious new threat; Alex confesses a secret to Maggie; a citizen of National City has a mysterious connection to Kara; Lena makes a bold move.
Supergirl challenges Rhea to battle to save National City. Meanwhile, Superman returns and Cat Grant offers Supergirl some sage advice.
Supergirl struggles to decide with whether or not to obey the President's orders regarding Rhea's latest actions. Meanwhile, Cat Grant returns to National City.
National City is attacked by a Phorian, a normally peaceful race with telekinetic abilities.
When Alex is kidnapped, Supergirl and Maggie must work together to save her.
Lena's ex-boyfriend Jack Spheer comes to National City to reveal his breakthrough in nanotechnology that has the potential to eliminate all diseases.
Aliens attack National City with the intention of collecting a large bounty put out on Supergirl.
Supergirl goes on high alert when a new villain comes to National City. In other events, Winn's new girlfriend gets him in trouble with the law and the Music Meister attacks.
Alex and Kara realize they must break the rules to foil Cadmus' latest plot.
When Jeremiah Danvers is rescued from Cadmus, Alex and Kara are thrilled to have him back, but Mon-El is suspicious about his sudden return.
A magical imp called Mr. Mxyzptlk arrives on Earth and wreaks havoc on National City when Kara doesn't reciprocate his feelings.
Lena is arrested when Metallo breaks Lillian out of prison and evidence suggests that Lena is responsible.
A White Martian called Armek comes to National City with the intention of bringing M'gann back to Mars to be punished for her treason.
When Livewire apparently breaks out of prison, Supergirl sets out to recapture her.
While searching for a missing woman, Supergirl and Mon-El end up on another planet where Roulette leads a slave trafficking ring.
As Eliza comes to National City for Thanksgiving, Kara turns to Lena for help when Cadmus unleashes a virus that instantly kills aliens, then is asked by Barry Allen and Cisco Ramon for help with an alien invasion on their Earth.
Supergirl comes face-to-face with Cyborg Superman when she attempts to save Mon-El from Cadmus.
The Guardian arrives to lend a hand when an alien parasite drains Supergirl of her power. Mon-El contemplates his motives when he considers a new career. Alex faces a new reality.
Supergirl faces a ruthless new gang that's been given new alien technology by Cadmus.
Supergirl tries to stop an alien fight club run by Roulette, while Hank gets to know M'Gann.
Supergirl and the DEO are assigned to protect the President when an attack on her causes alien vs. human rights in National City to heat up. Alex investigates the case with Maggie Sawyer while Kara fears Mon-El may be responsible.
Supergirl and Clark team up to stop a new threat emerging in Central City; Alex feels left out while Kara's family stays in town; a pod comes crashing down to earth.
Supergirl is forced to do battle with an unexpected enemy as she risks everything - including her life - to stop Non and Indigo from destroying everyone on Earth.
Non and Indigo use mind control to make the citizens of National City their army, so Kara must find a way to save her friends.
Kara gains a new ally when the Flash arrives from an alternate universe and helps her fight the Silver Banshee and Livewire in exchange for her helping him return home.
J'onn J'onzz reveals how he met Jeremiah Danvers and assumed the identity of Hank Henshaw.
Kara travels to the Fortress of Solitude hoping to find information on how to defeat Indigo, a being from her past who can travel through the Internet. In the meantime, James and Lucy reach a crossroads in their relationship.
Kara battles the Master Jailer while dealing with a second assistant at CatCo and disagreeing with James over the DEO's methods.
A parasitic alien attaches itself to Kara and traps her in a world where Krypton was never destroyed, leaving Alex, Hank and the DEO to fend off a Kryptonian attack without her.
Kara helps Hank face his painful past when a White Martian, who wiped out all of the Green Martians from Mars, kidnaps Senator Miranda Crane who is an anti-alien politician. Adam Foster who...
Kara does her best to support Winn when he hears that his father Winslow Schott Sr. breaks out of prison. His father looks for winn for a reason to become like him. Cat offers Lucy a job ...
A standoff ensues between the DEO and Astra's forces also Non kidnaps Hank, while Kara tries to refute Cat's allegations that she's Supergirl.
Kara and her friends are forced to rely on their inner strength and courage when an earthquake strikes National City, while Alex's mistrust of Hank reaches its breaking point when the ...
Stress makes Kara go too far during a training exercise against a military cyborg commissioned by General Sam Lane, while Cat's mother comes to visit and Winn helps Alex investigate her father's death.
Kara must protect National City from a series of bombings and babysit Cat's son, while James is visited by Lucy Lane.
Kara's foster mother visits for Thanksgiving, while an accident transforms a volatile CatCo employee into Livewire.
Supergirl's powers are put to the test when one of Superman's most formidable enemies, Reactron, shows up in National City to take her down. In the meantime, Cat makes plans to run an expose on Supergirl.
Kara must put doubts aside as she tries to apprehend an escapee from the Kryptonian prison; Cat pressure James for an interview with Supergirl.