Echoes

S3, E12: Teyla (Rachel Luttrell) begins to see apparitions of ancients in distress and believes they are the ghosts of the Ancients recently massacred by the Replicators. Meanwhile Rodney McKay (David Hewlett) believes he's found the whale that saved him a year ago while trapped in a submerged puddle jumper. But while taking a jumper out with Col. John Sheppard (Joe Flannigan) to investigate his old friend they discover the whale is not alone but is one of dozens of its kind all headed directly to Atlantis. With their high pitched sonar the whales begin to painfully effect the inhabitants of Atlantis. Teyla whose visions are now being shared by others believes it's this threat the whales pose that the ancients are trying to warn them about. Not till McKay discovers one of the Ancient's labs created to study and communicate with the whales does he realize that the whales are creating the apparitions. The visions are meant to warn Atlantis of a large scale coronal mass ejection from a nearby sun strong enough to destroy the city and all life on the planet. Without the necessary power the Ancients used to protect the planet from a similar disaster fifteen thousand years ago Sheppard improvises a plan to use their only ZPM aboard the Daedalus to block the blast above the ejection point. The plan however requires the Daedalus to fly almost directly into the sun.