The team race to Jacksonville in order to prevent another catastrophe like the one at the Manhattan office building, in which everyone bar one man died.
Anna enlists Ryan to help in efforts to eliminate the Fifth Column; the Vatican orders Father Travis to have Jack leave the church; Lisa meets her grandmother.
The team thinks they have discovered a synthetic gill that would allow humans to breathe underwater. A search for the doctor who created the gill sends them to a mental hospital. The doctor believes he is from Atlantis.