Arrival

The White House is gripped by a power struggle of historic proportions, pitting Martinez and Chief of Staff Peel against Jarvis and his secret ally, Sophia. Elsewhere, Sean, Vicky, Sterling, and Simon race to stop the dispersion points for the virus. Meanwhile, Leila fights for her life. But it all may be too late -- as the portal begins to open, sending tremors across the globe.

Aired: 2011-05-23