Our ancient enemies the Glfffltaaccchj (phonetic transliteration), remembered only in primordial dreams of reptile beings, fear of snakes, and stories of fabled Atlantis, have returned to wreak vengeance for their defeat 300,000 years ago. Last time around they successfully wiped our racial memories almost completely as they departed in defeat. The war was long, and resulted in the destruction of every "civilized" concentration of humans, as they were burned and melted to slag. But our heroic scientists managed to develop a virus that attacked their scales, making their life on Earth a nightmare of itching and scratching, with ugly festering sores. So they left, to wait until the few remaining humans, suddenly dropped back to pre-civilization conditions, finally died out.
But we survived! A dozen here, five there, a few hundred in some places, survived those first terrible winters or scorching summers and drowning monsoons. And now, to their dismay, the Glfffltaaccchj return to find that we have surpassed our own original level of technology!
The Glfffltaaccchj like their planets warmer and wetter than we do, much like the Age of Dinosaurs, when this was one of their favorite planets to come to for vacation. So they have deployed their evil planet-heating technology as a weapon, generating thousands of additional subsea volcanoes to raise the ocean temperature, melt the icecaps, and increase the greenhouse effect. And they have fired into the Sun a magnetic field generator that periodically triggers a huge CME aimed at the Earth to disrupt all electronics and destroy our high tech civilization once more. As their system gets tuned in, the CMEs will get larger and more dangerous.
This time they plan to cause us to die without destroying our physical infrastructure, so they can move right in. Huge seed-ships are already hiding in the Oort Cloud, waiting for the day when their generals can announce that our resistance is so little that we won't be able to fight back, and they can walk in and eat us.
Our only hope is to advance our technology faster than they can disrupt it. Since the Carrington Event 150 years ago, they have been tuning their CME generator, but it takes years to monitor and tweak between events, while avoiding a truly catastrophic effect on the Sun and making life on Earth impossible for millenia. So they have to wait, and monitor, and get ready. Already our technology has leaped ahead much faster than they could have imagined. Once we have successfully populated the Solar System, starting with orbital platforms, the Moon, Mars and the Asteroids, it will be too late for them. This is why human space development is so important. Support The Integrated Space Plan! (http://thespaceplan.com) and SAVE HUMANITY!! :D