Officially titled “Welcome to Earth,” the episode is officially described as follows:
“An attack is made on the President (guest star Lynda Carter) as hot-button, alien vs. human rights issues heat up in National City. Supergirl (Melissa Benoist) and the DEO are assigned to protect the President and bring in the responsible party. Alex (Chyler Leigh) teams up with Detective Maggie Sawyer (Floriana Lima) to investigate the case while Kara searches for a recently escaped Mon-El (Chris Wood), who she fears may be the alien behind the assault.
Supergirl stars Melissa Benoist alongside Mehcad Brooks as James Olsen, Laura Benanti as Alura Zor-El, Calista Flockhart as Cat Grant, Chyler Leigh as Alexandra “Alex” Danvers, Jeremy Jordan as Winslow “Winn” Schott, Jenna Dewan Tatum as Lucy Lane (sister of Lois), David Harewood as Hank Henshaw, Peter Facinelli as Maxwell Lord, with Dean Cain and Helen Slater. Supergirl season two also features recurring roles for Katie McGrath as Lena Luthor, Floriana Lima as Maggie Sawyer, and Lynda Carter as the President of the United States.