J'onn tell Alex and Kara that he's going to Mars to help M'gann. Kara insists on going with him. 

Eliza arrives in town for Alex and Maggie's shower and has dinner with the couple. 

M'gann tells J'onn that he's not the last Green Martian. His father is still alive. The White Martians are trying to find a staff that could track all the resistance members. They tell J'onn that he needs to get his father to help them find it first. 

Alex suggests that Maggie invite her parents to her shower. She initially dismisses the idea, but later calls her father. 

J'onn tries to talk to his father, but he assumes it's a trick. 

One of the resistance members gets impatient with J'onn and attacks M'gann. Kara and J'onn take his father back to his home. 

Maggie's dad arrives at the shower but storms out when he sees them kiss.

Kara gets through to J'onn's father and convinces him to give him a chance. J'onn shows his father a memory of his family and he finally believes it is him. He tells them where the staff is. 

Kara and J'onn help the resistance defeats the evil White Martians. 

Maggie says goodbye to her father. She tells Alex she is all she needs, but reiterates that she still doesn't want kids. 

J'onn's father returns to Earth with them.