Stargate Atlantis/Recap/S03/E12 Echoes

"McKay: A lot of animals--whales, dolphins... Zelenka: Pigeons. McKay: Are affected by the tiniest anomalies in the magnetosphere. It's as if their internal compasses were somehow, well...pigeons? Zelenka: Yeah, homing pigeons. I used to raise them before coming here. We used to consult solar charts before our pigeon races. McKay: Pigeon races?"

Rodney's old friend Sam the Whale has been spotted circling Atlantis. Why is he called Sam? Because "it's a boy's name too." Actually, Sam is not a whale, but a large species of fish called a Flagecallus by the Ancients - but we all know a Space Whale when we see one, so "whales" it is. And there sure do seem to be a whole heck of a lot of them. Sam is joined first by his mom, then by a few more pods, then by what seems like every freakin whale on the planet. Sheppard wonders if they make good eating.

Meanwhile, people around the city start seeing flashes - an ancient woman speaking gibberish, a burned man in a pilot's uniform. Teyla thinks they might be the ghosts of the slaughtered Ancients from the last couple of episodes. Ronon thinks they're the product of too much meditation. McKay manages to figure out that they (along with headaches and nosebleeds for everyone) are caused by the whales singing at them.

Fortunately, the city just happens to come with a bat -whale-song-decoder! The whales are replaying events that happened 15,000 years ago, stored in their genetic memories. It's a warning. The Lantean sun puts forth a massive coronal emission every - you guessed it - 15,000 years. Last time, the Ancients got warning and were able to extend their shield to protect much of the planet, but it was still a Mass Extinction Event with respect to the unprotected area. Those, of course, were shields powered by three ZPMs - after giving one to the SGC to power the Antarctic base and one to the Oddessy to help in the fight against the Ori, Atlantis only has one of the Asuran ZPMs left, not nearly enough to protect the planet.

The only option is to stop the coronal mass emission in its tracks. That is to say, fly the Daedalus up really close to the sun, boost its shields with the ZPM, and deflect the jet of hot plasma around it so that it misses the planet. Fortunately, these things don't last very long. The Daedalus gets a little toasted, but the planet is saved, and the whales return to doing whatever it is whales do.

Notably, this is the first episode in the show in which the major problem was in no way caused or exacerbated by the expedition itself.

Tropes
"Sheppard: Rodney! Canadian Football League is a joke! Celine Dion is overrated! Zelenka is smarter than you are!"
 * Eat the Dog: Sheppard suggests this with respect to Sam the Whale. McKay is justifiably horrified.
 * Genetic Memory: now with instant playback capabilities.
 * Moral Dissonance: Caldwell suggests nuking the whales. Really?
 * Not Listening to Me, Are You?: Before McKay's hearing has recovered, Sheppard tries to get his attention:


 * Psychic Nosebleed
 * Stock Episode Titles: 24 uses