SARD's Discovery 2 line of vessels, utilizing a barely-understood technology recovered from the alien ruins on Titan, utilized a sensitive form of gravity wave detectors to locate three "jump points" in the solar system, the closest one just beyond the orbit of Saturn.
The first one took ships to Proxima Centauri, where two barren planets were discovered. In hopes of finding connections to further star systems, two vessels began scanning the system for more jump points. The other two jump points connected to the heart of the Alpha Centauri system and to Gelise 368. No planets were found orbiting 368, but Alpha Centauri has one planet which seems to be very nearly habitable already and very conductive to terraforming.
After weeks of scanning, the Proxima expedition picked up a small but hot thermal signature- an alien spacecraft! The crew attempted to communicate with the aliens with a broad set of radio greetings and hull lights. Perhaps the aliens took this as preparations for an attack. It is unknown what, if anything they thought. Moments later, the Discovery vessel was annihilated by a nuclear missile...
So yeah, one jump away from earth, there is a alien warship with level-eight nukes. I have three PDCs with size-two countermissiles. I don't even have fighter engines. What I do have:
Ten military magento-plasma drives
A Neutronium shortage
One naval shipyard, though it is nice and large and has five slipways
My current plan is to reorganize all research to make some designs for combat- the smallest torpedo ships I can design, little more than FACs really. Start building more engines and components, putting all civilian construction on hold. Since I only have to move these one jump, and I only have efficiency 4 drives, I will makes these vessels conventional and instead have them cover the jump points. I will meanwhile use a gate ship to make a one-way passage, and then scout out proxima very cautiously, assuming the aliens have not moved into the solar system yet.
My biggest fear is that I will end up besiged by the aliens before my torpedo ships are ready. If they turn proactive, we're in trouble.