S2, E16: 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 (recurring guest star EMMANUELLE VAUGIER) 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.