Martha is seriously sickened by meteor dust, and Clark and Jonathan desperately try to help her. But when Clark becomes infected as well, he finds out just how vulnerable he can be. Only a miracle can save Clark and his mother -- and the amazing secret she holds within. Meanwhile, Lex confronts his feelings for Helen as she considers an enticing out-of-town research position. And Chloe and Lana cope with the unthinkable possibility that they may lose Clark forever.

Season 2 | Episode 16

Allison Mack

as Chloe Sullivan

Annette O'Toole

as Martha Kent

Erica Durance

as Lois Lane

John Schneider

as Jonathan Kent

Kristin Kreuk

as Lana Lang

Michael Rosenbaum

as Lex Luthor

Tom Welling

as Clark Kent