Kara must help Hank face his painful past when a White Martian, a member of the alien race that wiped out his people, kidnaps Senator Miranda Crane, an anti-alien politician. Also, Cat's estranged son, Adam, arrives in National City.

Supergirl is ensnared by an alien plant that forces her into her deepest desire, and her friends and sister must free her before it's too late. Meanwhile, the Kryptonians launch their plan to bring humanity to its knees and save Earth.