When the team treats a patient who has to decide between a dangerous surgery that could change his life or remain the same, he asks Dr. Shaun Murphy what he would do if he had that same choice.
Joe and Marybeth try to reconnect as Joe is shut out of the murder investigation. Nate and Cricket seek answers to past secrets while on the run.
A Secret Service agent ends up questioning his own sanity as he searches for two missing colleagues in a strange town that he seemingly can't escape.
In Camelot, as Mary Margaret and David attempt to retrieve the Dark One dagger, Emma uses a dreamcatcher to look into the past to see how Merlin was transformed into a tree. Together, Emma and Regina figure out the critical ingredient they must acquire to free Merlin, but it's a race against Arthur, who does not want Merlin released.
The team learns that a storm of catastrophic proportions is headed straight for the city of Atlantis. Without enough energy to power the shields Dr. Weir (Torri Higginson) orders that Atlantis be evacuated until the storm passes. But Dr. McKay (David Hewlett) conceives of a last minute plan to save the city--harness the power of the electrical storm to fuel the shields. Meanwhile unbeknownst to the Atlantis team the Genii have learned of AtlantisΓÇÖ evacuation and devise a dangerous plan to take over the cityΓÇÖs weapons for themselves. With Weir and McKay taken hostage and Lt. Ford (Rainbow Sun Francks) and Teyla (Rachel Luttrell) aiding the evacuees it is up to Major Sheppard (Joe Flanigan) to shut down the remaining grounding stations and save Atlantis from invasion before the storm hits.
