Supergirl and Superman team up to stop a new threat emerging in National City. A Kryptonian pod comes crashing down to Earth.

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 tries to stop an alien fight club run by Roulette, while Hank gets to know M'Gann.

Supergirl faces a ruthless new gang that's been given new alien technology by 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 comes face-to-face with Cyborg Superman when she attempts to save Mon-El from Cadmus.

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.

While searching for a missing woman, Supergirl and Mon-El end up on another planet where Roulette leads a slave trafficking ring.

When Livewire apparently breaks out of prison, Supergirl sets out to recapture her.

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.

Lena is arrested when Metallo breaks Lillian out of prison and evidence suggests that Lena is responsible.

A magical imp called Mr. Mxyzptlk arrives on Earth to woo Kara, and wreaks havoc on National City when she doesn't reciprocate his feelings.

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.

Alex and Kara realize they must break the rules to foil Cadmus' latest plot.

Supergirl goes on high alert when a new villain comes to National City. Meanwhile, Winn's new girlfriend Lyra gets him in trouble with the law and the Music Meister attacks.

Aliens attack National City with the intention of collecting a large bounty put out on Supergirl.

Lena's ex-boyfriend Jack Spheer comes to National City to reveal his breakthrough in nanotechnology that has the potential to eliminate all diseases.

When Alex is kidnapped, Supergirl and Maggie must work together to save her.

National City is attacked by a Phorian, a normally peaceful race with telekinetic abilities.

Supergirl struggles to decide whether or not to obey the President's orders regarding Rhea's latest actions. Meanwhile, Cat Grant returns to National City.

Supergirl challenges Rhea to battle to save National City. Meanwhile, Superman returns and Cat Grant offers Supergirl some sage advice.