Craig Veroni

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.

Dr. Rodney McKay (David Hewlett) undergoes experimental gene therapy altering his DNA to match the Ancient genetic coding. The experiment opens up countless scientific possibilities as well as an unexpected problem. Meanwhile during a game of hide and seek one of the Athosian children inadvertently opens a containment unit that lets loose a seemingly harmless black ethereal cloud. But when Atlantis goes through a series of technical malfunctions they realize that the shadowy creature is actually feeding off of the power supply!

Fleeing from a surprise encounter with the Wraith Major Sheppard (Joe Flanigan) falls victim to an alien symbiote which is feeding off his life force and slowly paralyzing him. While speeding back to Atlantis for medical aid the team gets trapped halfway through the Stargate when the puddle jumper damaged in the altercation with the Wraith suffers a mechanical failure. With only thirty-eight minutes before the Stargate shuts down Lieutenant Ford (Rainbow Sun Francks) and Dr. McKay (David Hewlett) struggle to manually fix the problem. As the clock ticks away the Atlantis team must come together or perish in the harsh vacuum of space.

Clark discovers the reason he was sent to Earth after a nightmare foretells a horrible event that's about to befall Smallville, and he visits the cave to seek answers from Jor-El. His biological father tells Clark he must reunite the three crystals immediately or an enormous disaster will devastate the planet that even Clark won't be able to stop or survive. Meanwhile, after finding Lana with Genevieve Teague's dead body, Lex helps the teen escape Smallville then takes shocking action to get one of the crystals away from Lionel. Realizing the elements are connected to Clark, Chloe tries to stop Lex from discovering the truth.

With the Wraith armada closing in on Atlantis Dr. McKay (David Hewlett) and a small team attempt to repair an ancient weapons satellite in the hopes of leveling the odds in the coming battle. Meanwhile tension builds between Teyla and some of the other members of the Atlantis team over her connection to the Wraith. Major Sheppard (Joe Flanigan) steps in to defend her but even he begins to harbour doubts when a team member is left unconscious after an attack by an unknown assailant.