When Jeremiah Danvers is rescued from Cadmus, Alex and Kara are thrilled to have their father back. The Danvers arrange a family dinner to celebrate but things go awry when a suspicious Mon-El starts to question Jeremiah about his sudden return.
When Mr. Mxyzptlk, a magical imp, shows up on Earth and declares his love for Kara, she tries to let him down easy, thinking him harmless. However, he decides it’s a challenge and starts to wreak havoc on National City. Mon-El has seen beings like Mr. Mxyzptlk on Daxam and knows how dangerous they can be. He and Kara argue over how to get rid of Mr. Mxyzptlk, further straining their relationship. Meanwhile, Alex and Maggie celebrate their first Valentine’s Day together.
After Metallo breaks out of prison and frees Lillian Luthor, the police blame Lena for his escape and arrest her. Despite overwhelming evidence, Kara refuses to believe her friend is guilty and fights to clear Lena’s name. Flashbacks reveal how Lena came to be a Luthor. Meanwhile, Alex and Maggie celebrate their first Valentine’s Day together.