Marc Menard

Kate learns that someone knows the secret of Aaron's parentage; the dramatic shifts through time endanger the remaining island survivors.

Locke shoulders the burden of ending the island's increasingly violent movements through time; Ben is stymied in his efforts to reunite the Oceanic 6 and bring them back to the island.

Dr. House annoys his boss when he suggests that two sick newborns in the hospital are the start of an epidemic; but as more babies fall ill, the maternity ward closes and the doctors battle over courses of treatment.