The event is set to run until April 27 at 10a PDT. It seems that the Elachi are invading the Alpha Quadrant and kidnapping people. It’s up to you to stop them.
“A joint fleet has gathered here to stop them. The fleet consists of science ships that have disabled their weaponry in order to divert all available resources to disabling the gate. We’ll need to protect them from the Elachi until they finish their work.”
In related news, a three week long double XP event is set to run from April 24 through May 15. You can grab double XP for any character, whether it’s a brand new one or an alt you’ve forgotten about. You can learn more details on the event here.